SWEET HOME MITIGATION PLAN

Transcription

1 SWEET HOME MITIGATION PLAN A MULTI-HAZARD MITIGATION PLAN CITY OF SWEET HOME, OREGON Updated August 2015

2 Cover Photo: Foster Dam and Reservoir East and Upstream of the City of Sweet Home City of Sweet Home August 2015 Sweet Home Mitigation Plan August 2015

3 ACKNOWLDEGEMENT This Sweet Home Mitigation Plan (SHMP) was formerly known as the Sweet Home Multi- Hazard Mitigation Plan. The original Multi-Hazard Mitigation Plan was first researched and written in by Goettel and Associates Inc. 1 with vigorous review and input of local knowledge and values by concerned citizens on the Mitigation Committee, and in public meetings, as well as by the dedicated City staff that participated in the ongoing planning process over many months of effort. This Plan has been updated at five year intervals since 2004 with contemporary information, data, and citizen/staff input. Yet, Ken Goettel s original insights and work on hazard mitigation planning continue to form the foundation of these updated City of Sweet Home mitigation plans and the ongoing mitigation planning efforts of the community. TCL Planning Consultants 2 assisted Ken Goettel in the process by working on background information and related hazard assessment documents. The City of Sweet Home asked TCL to facilitate this 2015 update; this new update of the SHMP remains in keeping with Goettel s original work. 1 Goettel & Associates Inc.: ; ; 1732 Arena Drive Davis, CA TCL Planning Consultants (T. & C. Lewis): Sweet Home, Oregon. City of Sweet Home August 2015 Sweet Home Mitigation Plan August 2015

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5 EXECUTIVE SUMMARY OVERVIEW OF THE SWEET HOME MITIGATION PLAN (SHMP) The Sweet Home Mitigation Plan was formerly known as the Sweet Home Multi-Hazard Mitigation Plan. The SHMP is, of course, still a multi-hazard mitigation plan for the City of Sweet Home and covers each of the major natural and human-caused hazards that pose risks to the City. The primary objectives of this Sweet Home Mitigation Plan (SHMP) are to reduce the negative impacts of future disasters on the community, including: (1) saving lives and reducing injuries; (2) minimizing damage to buildings and infrastructure (especially critical facilities); and, (3) minimizing economic losses. This Mitigation Plan is a planning document, not a regulatory document. The SHMP meets FEMA s planning requirements by addressing hazards, vulnerability and risk. document the following working definitions are used: In this Hazard -- the frequency and severity of disaster events; Vulnerability -- the value, importance, and fragility of buildings and infrastructure; Risk -- the threat to people, buildings and infrastructure, taking into account the probabilities of disaster events. Adoption of a multi-hazard mitigation plan is required for communities to remain eligible for future FEMA mitigation grant funds. This City of Sweet Home Mitigation Plan includes the following parts and chapters: Cover Acknowledgement Copy of City Council Resolution of Adoption Executive Summary Table of Contents Chapter 1: Introduction Chapter 2: Community Profile: City of Sweet Home Chapter 3: Community Involvement and Public Process Chapter 4: Mission Statement, Goals, Objectives and Action Items Chapter 5: Plan Adoption, Implementation, and Maintenance Chapter 6: Floods Chapter 7: Severe Storms Chapter 8: Landslides Chapter 9: Wildland/Urban Interface Fires Chapter 10: Earthquakes Chapter 11: Volcanic Hazards Chapter 12: Dam Failures Chapter 13: Disruption of Utility and Transportation Systems Chapter 14: Hazardous Materials Chapter 15: Terrorism Appendices Appendix 1: Synopsis of FEMA Grant Programs Appendix 2: Principles of Benefit-Cost Analysis Appendix 3: Community Involvement Documentation City of Sweet Home August 2015 Sweet Home Mitigation Plan Page ES - i

6 CHANGES MADE TO THE 2009 SHMP IN THE 2015 UPDATED SHMP The entire document has been proofed and edited for clarity and grammatical correctness. The following table describes the substantive changes made to the 2009 Plan for the 2015 Update. Substantive Changes made to the 2009 Plan for the 2015 Update (see Table 3-1) (For detailed changes in Mitigation Action Items, see Table 4-1, page 4-4 in Chapter 4.) Chapter Section Substantive Changes Acknowledgements xxxxxxx Acknowledgment added Adopt Resolution xxxxxxx Copy of Signed Resolution of Adoption (by City Council) moved from end of Chapter 5 Executive Sum Table of Cont. xxxxxxx xxxxxxx Executive Summary updated Table of Contents updated Added Subsection titles and new Figure 1-1 (page 1-3) and 1-2 (page 1-4) Hazard cross indexing added ( Mitigation Plan with 2012 EOP) Section # & title added outline of the rest of the document Updated demographic information with 2010 and 2011 data Update housing data to 2010 and 2012 data New subsection 3.1 (Overview) & other subsections re-numbered; Updated information on public process, including participation and notifications Updated information and subsection tiles added: pre-1996, 1996 & following; 2009 update process Updated the Sweet Home Mitigation Planning Committee (SHMPC) information Updated the process information Updated change tracking for 2015 Plan Updated Resources and References Refined Objectives Clarification in wording of Goal 4, and Objectives A & B for Goal 6 (page 4-3) Updated Mitigation Action Items (see Table 4-1) 4 Table 4-2 Multi-Hazard: Table updated, modified to more directly represent Plan Goals 4 Table 4-3 Flood - inside FEMA Mapped flood plain: Table updated, modified to more directly represent Plan Goals 4 Table 4-3 Flood - outside FEMA Mapped flood plain: Table updated, modified to more directly represent Plan Goals 4 Table 4-4 Severe Storm: Table updated, modified to more directly represent Plan Goals 4 Table 4-5 Landslide: Table updated, modified to more directly represent Plan Goals 4 Table 4-6 Wildland/Urban Interface Fire: Table updated, modified to more directly represent Plan Goals 4 Table 4-7 Earthquake: Table updated, modified to more directly represent Plan Goals 4 Table 4-8 Volcanic Hazards: Table updated, modified to more directly represent Plan Goals 4 Table 4-9 Dam Failure: Table updated, modified to more directly represent Plan Goals 4 Table 4-10 Utility - Transportation: Table updated, modified to more directly represent Plan Goals 4 Table 4-11 Hazmat: Table updated, modified to more directly represent Plan Goals 4 Table 4-11 Terrorism: Table updated, modified to more directly represent Plan Goals Updated adoption information Added information on process for updating existing mechanisms Added information: completed South Santiam Watershed Council project (Ames Creek) Updated maintenance schedule (summarized in Table 5-2, on page 5-6) Updated date of the Sweet Home Flood Insurance Study Updated information on the Flood Insurance Rate Map designations Updated information from the Flood Insurance Rate Map Updates events since Updated the number of policies in the NFIP in Table 6-2 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] 7 New Now titled Severe Storms. Previously this chapter had been entitled Winter Storms, but has been Chapter renamed in recognition of the fact that although severe storms are more likely to occur in the winter Title months, they can occur during any season of the year Updated tornado information Updated wind hazard data Updated web page information and severe storm data City of Sweet Home August 2015 Sweet Home Mitigation Plan Page ES - ii

7 Substantive Changes made to the 2009 Plan for the 2015 Update (see Table 3-1) (For detailed changes in Mitigation Action Items, see Table 4-1, page 4-4 in Chapter 4.) Chapter Section Substantive Changes Subsections & (page 7-6) added (updates events since 2009) Updated historical severe storm data 7 Table 7-5 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Inserted update to Subsections renumbered as 8.4 and Table 8-2 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Subsection 9.1 Overview title inserted All subsections renumbered Updated NFPA data to Updated NFPA data to Updated data to Updated Historical Data for Wildland Fires in Oregon Added Sweet Home Fire and Ambulance District Data for Table 9-4 Added Wildland and Wildland/Urban Fires in Linn County in ODF Protection Areas table 9 Table 9-5 Added distribution of fire sizes table Subsection renumbered as Inserted update to Table 9-8 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] 10 Table 10-2 Updated USGS Seismic Hazard Data for Sweet Home 10 Table 10-4 Updated USGS Seismic Hazard Map for Oregon Updated Figure 10-3 with USGS 2012 Oregon Seismicity Map Subsections renumbered Added information on earthquake events since Updated building damage estimates, injuries, and deaths estimates 10 Table 10-3 Updated M8.5 Cascadia Subduction Zone Interface Earthquake table 10 Table 10-4 Updated M7.5 Cascadia Subduction Zone Intraplate Earthquake table Updated information on water treatment plant 10 Table 10-6 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Added information on volcanic events since Subsections renumbered. 11 Table 11-4 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] 12 Title Title of Chapter and Hazard changed from Dam Safety to Dam Failures Updated National Inventory of Dams data 12 Table 12-2 Updated Numbers of Dams by NID Potential Hazard Categories 12 Table 12-3 Updated NID High Potential Hazard Dams in Linn County Added information on dam events since Subsections renumbered Added 2013 Seismic Safety Review conducted by US Army Corps of Engineers Subsection # 12.8 added for References 12 Table 12-7 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Introductory paragraphs given subsection # Subsections renumbered Removed Sweet Home airport which has officially been closed City of Sweet Home August 2015 Sweet Home Mitigation Plan Page ES - iii

8 Substantive Changes made to the 2009 Plan for the 2015 Update (see Table 3-1) (For detailed changes in Mitigation Action Items, see Table 4-1, page 4-4 in Chapter 4.) Chapter Section Substantive Changes Updated information on transportation or utility disruption events since Table 13-3 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Updated information to remove Sweet Home water treatment plant on 9 th Avenue Updated information on hazmat events since Renumbered as subsection Subsection # added for References Cited in this Chapter 14 Table 14-7 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Updated information on terrorism events since Renumbered as subsection Table 15-3 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] City of Sweet Home August 2015 Sweet Home Mitigation Plan Page ES - iv

9 ACTION ITEM CHANGES SINCE 2009 Action Item Changes from the 2009 Plan to the 2015 Plan (See Table 4-1) (MAI = Mitigation Action Item; ST = Short Term; LT = Long Term; CFs = Critical Facilities) MAI # MAI Brief Description Change Table 4-2: Multi-Hazard MAI (Chapter 4, page 4-6) ST 3 Neighborhood self-help groups for hazard emergencies. Reworded for clarity. ST 4 Access needs of emergency shelters. Reworded for clarity. ST 5 Preparedness programs Reworded for clarity. ST 6 Public/private partnership for mitigation Reworded for clarity. ST 7 City Web Page for emergency preparedness information for public. NEW LT 3 Neighborhood emergency self-help groups Reworded for clarity. LT 4 Integrate SHMP findings into City planning/regulatory documents Reworded for clarity. LT 5 Information for neighborhoods during emergencies. Delete Replaced by ST 7 Table 4-3: Flood MAI (Chapter 4, p. 6-14)/Same as Table 6-2 (Chapter 6, p.6-14) ST 1 FEMA Mapped: Update of 1982 FIS for Sweet Home. Completed in 2010, thus deleted. ST 1 Begin land use code changes vis-à-vis storage in flood plains. NEW LT 2 Outside FEMA Maps: Fund storm water treatment project. Completed and therefore deleted. Table 4-4: Severe Storm MAI (Chapter 4, p. 4-8)/Same as Table 7-5 (Chapter 7, p. 7-10) ST 1 Assess needs for generators in emergency shelters Split & reworded from old ST#.1 ST 2 Accessing vulnerable population within SH. Coordinating organizations changed. LT 3 Evaluate feasibility of solar/wind powered radios, etc. Completed - Not Viable deleted. LT 3 Continuing addressing back-up generator needs for City CFs Split & moved, clarified (old ST#1). LT 4 Tree trimming along main electrical lines Short term work completed, and the LT 5 Tree trimming along electrical lines to individual customers. ongoing maintenance moved to LT Table 4-5: Landslide MAI (Chapter 4, p. 4-9)/Same as Table 8-2 (Chapter 8, p. 8-7) ST 1 Design/implement mitigation project for specific slope areas. Completed and therefore deleted. ST 2 Inventory locations/structures subject to landslides. Completed and therefore deleted. ST 1 Implement Geo-tech work in previously identified slide areas. NEW Table 4-6: Wildland/Urban Interface Fire MAI (Chapter 4, p. 4-10)/Same as Table 9-8 (Chapter 9, p. 9-18) LT 2 Coordinate SH fire plans with Linn County, USFS and ODF. Completed and therefore deleted. LT 3 Road signage for evacuation routes. Evaluated - Not Viable deleted. LT 2 Continue fuels reduction projects & public education. ST completed, moved to LT (old ST1) Table 4-7: Earthquake MAI (Chapter 4, p. 4-11)/Same as Table 10-6 (Chapter 10, p ) ST 1 Brief EQ Inventory of vulnerable important buildings. Reworded for clarity. Moved to LT #1. ST 2 EQ Inventory of vulnerable residential/commercial buildings. Reworded for clarity. Moved to LT #2. ST 3 FEMA pamphlets & public EQ awareness. Reworded for clarity. Renumbered ST#1. LT 1 Seek funding for retrofitting important buildings. Reworded for clarity. Renumbered LT#3. LT 2 Addresses CFs & Emergency Shelters. Reworded for clarity. Renumbered LT#4. Table 4-8: Volcanic Hazards MAI (Chapter 4, p. 4-12)/Same as Table 11-4 (Chapter 11, p. 11-7) ST 1 Update Public notification procedures for ash-falls. Completed and therefore deleted. ST 2 Update emergency response planning for ash-falls. (2012 EOP) Completed and therefore deleted. Table 4-9: Dam Failure MAI (Chapter 4, p. 4-12)/Same as Table 12-7 (Chapter 12, p ) xxx Tile of Table was Dam Safety but was changed to Dam Failure to accurately portray the hazard. ST 1 Part b: Public notification procedures & evacuation routes. Addressed & therefore deleted. ST 1 Part a: Obtain maps of dam failure inundation. Not completed and thus retained. Reworded for clarity. ST 3 Work with Linn Co call system for emergency response. Completed and therefore deleted. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page ES - v

10 Continued Action Item Changes from the 2009 Plan to the 2015 Plan (MAI = Mitigation Action Item; ST = Short Term; LT = Long Term; CFs = Critical Facilities) MAI # MAI Brief Description Change Table 4-10: Utility & Transportation System Disruption MAI (Chapter 4, p. 4-13)/ Same as Table 13-3 (Chapter 13, p ) ST 1 Addresses CFs & Emergency Shelters. Reworded for clarity. ST 3 Update emergency response plans. Completed and therefore deleted. ST 4 Red flag notification system. Addressed & therefore deleted. LT 1a Emergency potable water filling station. [Part of old LT 1] Split from LT 1 & reworded to clarify LT 1b Portable potable water source. [Part of old LT 1] Split from LT 1 & reworded to clarify LT 2 Enhanced communication/coordination with local ARES. Reworded for clarity. LT 3 Educate/encourage residents to stock emergency supplies moved to LT (old ST 2) LT 4 Increase fuel storage capacity for emergency backup New Table 4-11: HAZMAT Incident MAI (Chapter 4, p. 4-14)/Same as Table 14-7 (Chapter 14, p ) LT 1 Update site-specific lists of hazardous materials in SH (old ST1) Addressed in ST; reworded to clarify LT 2 Enhance emergency planning & agency coordination (old ST 2) Addressed in ST/moved to LT Table 4-12: Terrorism MAI (Chapter 4, p. 4-14)/Same as Table 15-3 (Chapter 15, p ) ST 2 Educational brochures for public awareness. Addressed in ST thus deleted. LT 1 Enhanced planning, coordination, training (old St 1) Addressed in ST/moved to LT/clarified LT 1 Update physical security & response water system [old LT 1] Completed therefore deleted. LT 2 Enhanced planning, training, equipment Reworded for clarity. Renumbered LT#1. LT 3 Enhanced security for other CFs. Reworded for clarity. Renumbered LT#2. MAI# MAI Brief Description Change City of Sweet Home August 2015 Sweet Home Mitigation Plan Page ES - vi

11 Continued Action Item Changes from the 2009 Plan to the 2015 Plan (MAI = Mitigation Action Item; ST = Short Term; LT = Long Term; CF = Critical Facility) City of Sweet Home August 2015 Sweet Home Mitigation Plan Page ES - vii

12 MAI # MAI Brief Description Change Table 4-11: HAZMAT Incident MAI (Chapter 4, p. 4-14)/Same as Table 14-7 (Chapter 14, p ) LT 1 Update site-specific lists of hazardous materials in SH (old ST1) Addressed ST; reworded to clarify LT 2 Enhance emergency planning & agency coordination (old ST 2) Addressed ST/moved to LT Table 4-12: Terrorism MAI (Chapter 4, p. 4-14)/Same as Table 15-3 (Chapter 15, p ) ST 2 Educational brochures for public awareness. Addressed in ST thus deleted. LT 1 Enhanced planning, coordination, training (old ST 1) Addressed in ST/moved to LT/clarified LT 1 Update physical security & response water system [old LT 1] Completed therefore deleted. LT Enhanced security for other CFs. Reworded for clarity. MAI# MAI Brief Description Change City of Sweet Home August 2015 Sweet Home Mitigation Plan Page ES - viii

13 TABLE OF CONTENTS COVER PHOTO NOTATION ACKNOWLEDGEMENTS SIGNED CITY COUNCIL RESOLUTION ADOPTING THE 2015 UPDATED SWEET HOME MITIGATION PLAN EXECUTIVE SUMMARY 1.0 INTRODUCTION What is a Mitigation Plan? Why is Mitigation Planning Important for Sweet Home? The Sweet Home Mitigation Plan (SHMP) Key Concepts and Definitions The Concept of Mitigation Planning: Risk Reduction Risk is the Combination of the Threat or Hazard Event and Vulnerability or Exposure Threat or Hazard Event Vulnerability and Exposure Risk Mitigation The Mitigation Process The Role of Benefit-Cost Analysis in Mitigation Planning Hazard Synopsis Outline of the Remainder of the SHMP COMMUNITY PROFILE: CITY OF SWEET HOME Population and Demographics Geography and Climate Land and Development Housing in Sweet Home COMMUNITY INVOLVEMENT AND PUBLIC PROCESS Community Involvement in Sweet Home s Mitigation Planning Previous Mitigation Planning Activities Before Post February 1996 Flood Event Sweet Home Multi-Hazard Mitigation Master Plan The 2009 Update of the Sweet Home Multi-Hazard Mitigation Plan All Hazard Mitigation Planning Committee Plan Update Process Changes Made to the 2009 SHMP in the 2015 Updated SHMP Resources and References MISSION STATEMENT, GOALS, OBJECTIVES AND ACTION ITEMS Overview Four-Step Mitigation Planning Framework Mission Statement Mitigation Plan Goals and Objectives Sweet Home Hazard Mitigation Plan Action Items City of Sweet Home August 2015 Sweet Home Mitigation Plan TOC - i

14 5.0 MITIGATION PLAN ADOPTION, IMPLEMENTATION AND MAINTENANCE Overview Plan Adoption Implementation Implementation Through Existing Programs Cost Effectiveness of Mitigation Projects STAPLE/E Approach Maintenance FLOOD HAZARDS Overview Historical Floods in Sweet Home The February 1996 Flood The 1998 Flood Flood Events Since Flood Hazards and Flood Risk: Within Mapped Floodplains Overview Flood Hazard Data Caveats for the Sweet Home Flood Insurance Study Interpreting Flood Hazard Data for Mapped Floodplains Flood Hazards and Flood Risk: Outside of Mapped Floodplains Inventory Exposed to Flood Hazards in Sweet Home Flood Insurance Data for Sweet Home Estimating Flood Losses and Flood Risk Flood Mitigation Projects SEVERE STORMS Overview Severe Storms Hazard Assessment Rain Hazard Data Wind Hazard Data Historical Severe Storm Data for Sweet Home Severe Storm Events Since 2009 Update of the SHMP Potential Changes in Global Climate: Implications for Local Mitigation Planning Severe Storm Risk Assessment Mitigation of Severe Storm Impacts LANDSLIDES Landslide Overview and Definitions Landslide Hazard Assessment Landslide Events Since Landslide Risk Assessment Mitigation of Landslide Risk WILDLAND/URBAN INTERFACE FIRES Overview Fire Primer Structure Fires Wildland Fires City of Sweet Home August 2015 Sweet Home Mitigation Plan TOC - ii

15 Wildland/Urban Interface Fires Measures of the Level of Fire Hazard Observed Fire Danger Class Maps Fire Potential Index Map Other Maps Historical Data for Wildland Fires in Oregon Urban/Wildland Interface Fire Hazards for Sweet Home Overview and Background Information Historical Fire Date for Linn County and Sweet Home Wildland/Urban Interface Fire Events Since Mitigation Strategies Reduce the Probability of Fire Ignitions Reduce the Probability that Small Fires Will Spread Minimize Property Damage Minimize Life Safety Risk EARTHQUAKES Overview and Earthquake Primer Overview Primer Seismic Hazards for Linn County and Sweet Home Earthquake Events Since Other Aspects of Seismic Hazards in Linn County Liquefaction Landslides Dam Failures Tsunamis and Seiches Risk Assessment for Scenario Earthquakes Richter Magnitude 8.5 Cascadia Subduction Zone Interface Earthquake Richter Magnitude 7.5 Cascadia Subduction Zone Intraplate Earthquake Earthquake Risk Assessment: Technical Guidance Level Two Risk Assessment Level Three Risk Assessment Seismic Windshield Survey for Sweet Home Earthquake Hazard Mitigation Projects VOLCANIC HAZARDS Overview Volcanic Hazard Types Volcanic Hazards for Linn County and Sweet Home Volcanic Events Since the 2009 Update of the SHMP Mitigation of Volcanic Hazards DAM FAILURES Overview of Dams Dam Primer Dam Nomenclature and Types of Dams Dam Failure Modes Oregon Dam Data Dam Failure Hazard Assessment: Sweet Home Dam Failure Events Since the 2009 Update of the SHMP Risk Assessment (Preliminary) City of Sweet Home August 2015 Sweet Home Mitigation Plan TOC - iii

16 Flood Damage to Dams Earthquake Damage to Dams Loss Estimates (Preliminary) Mitigation Strategies and Recommendations References DISRUPTION OF UTILITY AND TRANSPORTATION SYSTEMS Overview Transportation Systems Utility Systems - Overview Potable Water Systems Wastewater Systems Natural Gas Systems Telecommunications Systems Electric Power Systems Probable Impacts on City of Sweet Home Transportation or Utility Disruptions Since the 2009 Update of the SHMP Mitigation Action Items HAZARDOUS MATERIALS Introduction Effects of Hazardous Materials on Humans Classification Systems and Emergency Response Protocols Statutory and Regulatory Context Fixed Site Hazardous Materials Locations Hazardous Materials Transport: Truck, Rail and Pipelines Summary of Probable Impacts on City of Sweet Home Hazmat Incidents Since the 2009 Update of the SHMP Summary and Mitigation Strategies Planning and Response Mitigation Measures References TERRORISM Overview Threat Spectrum Terrorism Incidents Since Mitigation Actions APPENDICES... A1-1 APPENDIX 1 SYNOPSIS OF FEMA GRANT PROGRAMS... A1-1 APPENDIX 2 PRINCIPLES OF BENEFIT-COST ANALYSIS... A2-1 APPENDIX 3 COMMUNITY INVOLVEMENT DOCUMENTATION... A3-1 City of Sweet Home August 2015 Sweet Home Mitigation Plan TOC - iv

17 1.1 What is a Mitigation Plan? 1.0 INTRODUCTION The City of Sweet Home and surrounding areas are subject to a wide range of natural and human-caused hazards, including: floods, severe storms, landslides, earthquakes, dam failures, hazardous material spills, and many others. Some of these hazard events, such as severe storms, happen to some extent every year. Others, such as earthquakes, may only impact Sweet Home significantly once every few hundred years. The impact of potential future hazard events on Sweet Home may be minor (e.g., a few inches of water in a street) or it may be major, with damages and economic losses totaling millions of dollars. The impacts of major disasters on communities can be devastating. Total damages may include economic losses, casualties, and disruption, hardships and suffering are often far greater than the physical damages alone. Furthermore, recovery from major disasters often takes many years and some heavily impacted businesses and/or communities may never fully recover. Completely eliminating the risk of future disasters in Sweet Home is neither technologically possible nor economically feasible. However, substantially reducing the negative impacts of future disasters is achievable with the implementation of a pragmatic Hazard Mitigation Plan. Hazard mitigation reduces disaster damages and is defined as sustained action taken to reduce or eliminate the long-term risk to human life and property from hazards (Source: 44 CFR Mitigation Planning Definitions). This SHMP has several key elements. 1. Each hazard that may impact Sweet Home significantly is reviewed to determine the probability (frequency) and severity of likely hazard events. 2. The vulnerability of Sweet Home to each hazard is evaluated to determine the likely extent of physical damages, casualties, and economic impacts. 3. A range of mitigation alternatives are evaluated to identify those with the greatest potential to: reduce future damages and losses in Sweet Home, protect facilities deemed critical to the community s well being, and/or that are deemed highly valuable (politically, culturally or economically) by the community. 1.2 Why is Mitigation Planning Important for Sweet Home? Effective mitigation planning will help the residents of Sweet Home deal with natural and human-caused hazards realistically and rationally. Such planning helps identify specific locations in Sweet Home where the level of risk from one or more hazards may be unacceptably high and then helps find cost effective ways to reduce such risk. Mitigation planning strikes a pragmatic middle ground between unwisely ignoring the potential for major hazard events on one hand and unnecessarily overreacting to the potential for disasters on the other hand. Furthermore, the Federal Emergency Management Agency (FEMA) requires each local government entity to adopt a mitigation plan to remain eligible for future pre- or postdisaster FEMA mitigation funding. Thus, an important objective in developing this plan is to maintain eligibility for FEMA funding and to enhance Sweet Home s ability to attract future FEMA mitigation funding. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-1

18 The Plan is specifically designed to help Sweet Home gather the data necessary to compete successfully for future FEMA funding of mitigation projects. FEMA requires that all FEMAfunded hazard mitigation projects must be cost-effective (i.e., the benefits of a project must exceed the costs). Benefit-cost analysis is thus an important component of mitigation planning, not only to meet FEMA requirements, but also to help evaluate and prioritize potential hazard mitigation projects in Sweet Home, regardless of whether funding is from FEMA, state or local government or from private sources. 1.3 The Sweet Home Mitigation Plan (SHMP) The Sweet Home Mitigation Plan was formerly known as the Sweet Home Multi-Hazard Mitigation Plan. This Plan is built upon a quantitative assessment of each of the major hazards that may impact Sweet Home, including their frequency, severity, and areas of the City likely to be affected. The hazards addressed include: floods, severe storms, wildland/urban interface fires, landslides, dam failures, earthquakes and others. The Sweet Home Mitigation plan also includes a quantitative assessment of the vulnerability of buildings, infrastructure, and people to each of these hazards. That is, the plan includes an evaluation of the likely magnitude of the impacts of future disasters on Sweet Home. These reviews of the hazards and the vulnerability of Sweet Home to these hazards are the foundation of the mitigation plan. From these assessments, specific locations where buildings, infrastructure, and/or people may be at high risk are identified. These high risk situations then become priorities for future mitigation actions to reduce the negative impacts of future disasters on Sweet Home. The Sweet Home Mitigation Plan deals with hazards realistically and rationally. It also strikes a balance between suggested physical mitigation measures to eliminate or reduce the negative impacts future of disasters and planning measures that better prepare the community to respond to and recover from disasters for which physical mitigation measures are not possible or are not economically feasible. 1.4 Key Concepts and Definitions The Concept of Mitigation Planning: Risk Reduction The central concept of mitigation planning is that mitigation reduces risk. Risk can generally be defined as the jeopardy or danger to which people and the built environment are exposed by hazards or threats. Risk is the potential for damages, losses and casualties arising from the negative impact of hazards on the built environment. Risk is generally expressed in terms of: (1) dollars (e.g., estimates of potential damages and other economic losses); and (2) casualties (numbers of deaths and injuries). The essence of mitigation planning for the community is to identify high risk locations/situations in Sweet Home and to evaluate ways to mitigate (reduce) the impacts of future disasters on these high risk locations/situations. There are four key concepts that govern hazard mitigation planning: hazard, vulnerability or exposure, risk and mitigation. Each of these key concepts is addressed in turn below. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-2

19 1.4.2 Risk is the Combination of the Threat or Hazard Event and Vulnerability or Exposure Generally speaking, the level of risk at a given location, building, facility or infrastructure depends on the combination of threat or hazard Figure 1-1: Risk is the event and vulnerability as illustrated in Figure 1-1. Combination of Threat/Hazard Event and Threat or Hazard Event Vulnerability or Exposure Threat or Hazard Event refers to natural or humancaused events that may cause damages, losses or casualties. Examples of threats or hazard events include floods, severe storms, landslides, earthquakes, hazardous material spills, human violence, and terrorism. Hazards are characterized by their frequency and severity as well as by the duration, speed of onset and the geographic area affected. Each hazard is characterized differently, with appropriate parameters for the specific hazard. For example, floods may be characterized by the (Source: TCL/K. Goettel) areas inundated, frequency of flooding, along with flood depth and flood velocity. Severe storms may be characterized by the amount of rainfall in a 24-hour period, or by wind velocity, temperature changes, and amount of snow, or ice associated with a storm. Earthquakes may be characterized by the severity and duration of ground motions, and so on. A hazard event, by itself, may not result in any negative impacts on a community. For example, a flood-prone five-acre parcel may typically experience several floods per year, even up to depths of several feet of water typically expected in say a 50-year flood event. The high frequency and severe nature of the flooding would lead one to conclude that flooding of this parcel is a hazard event or threat of high severity or magnitude. However, if the parcel is a wetland, with no structures or infrastructure, then there is no vulnerability. Because there is no vulnerability, clearly no people or any aspects of the built environment are endangered or jeopardized, and thus there is no risk. In this example, the very frequent and deep flooding (i.e., the high hazard) may be beneficial environmentally by providing wildlife habitat and recreational opportunities. Threat or hazard events do not produce risk to people and property, unless there is vulnerable inventory exposed to the hazard. Risk to people, buildings and/or infrastructure results only when hazards are combined with vulnerability or exposure Vulnerability and Exposure Vulnerability is the degree to which individuals, the community as a whole, the built environment, systems, other assets and resources, and cultural, economic, and social activity are susceptible to harm, degradation, or destruction. Vulnerability is specific to a particular location, which may be subject to one or more threats or hazard events. Exposure is the quantity, value and vulnerability of the built environment (inventory of people, buildings and infrastructure) in a particular location subject to one or more hazards. Vulnerability and exposure are overlapping and essentially synonymous terms for purposes of mitigation planning. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-3

20 Vulnerability primarily involves the inventory of people and the built environment in harm s way. Inventory can be characterized by the number, size, type, use, and occupancy of buildings as well as by the infrastructure present in any given specific location. Infrastructure includes bridges, roads and other transportation systems, utilities (e.g., potable water, wastewater, natural gas, and electric power), telecommunications systems, and so on. The various components of a community s inventory vary greatly in importance to the vitality and normal functioning of that community. Some types of facilities and infrastructure, critical facilities and critical infrastructure, are especially important to a community, particularly during emergency situations. Examples of critical facilities include police and fire stations, hospitals, 911 centers, emergency operations centers, and emergency shelters. Critical infrastructure include important utility links, utility lines, and life lines, that are essential in providing service to large numbers of people such as potable water, waste water sanitation, electricity, natural gas, and so on. Traditionally risk assessment focuses on not only inventory (persons present at a given site and the quantity and value of buildings or infrastructure present), but also by its vulnerability to each hazard under evaluation. For example, a given facility or infrastructure may or may not be particularly vulnerable to flood damages or earthquake damages, depending on its location as well as the details of its design and construction, but could be vulnerable to landslides and wildland/urban interface fires. Depending on the hazard, different measures of the vulnerability of buildings and infrastructure are often used Risk Risk is the threat to people and the built environment: the potential for damages, losses and casualties arising from hazards. Risk, which results only from the combination of Hazard and Exposure as discussed above, is illustrated in Figure 1-2. This photograph of downtown Ashland Oregon shows RISK, the combination of a hazard (flooding) with exposure of vulnerable inventory of people, buildings and infrastructure. If this flooding occurred in an undeveloped wetland (no vulnerability or exposure) there is no risk. Figure 1-2: Risk Results from the Combination of Hazard and Vulnerability or Exposure (Source: Ashland, Oregon) Risk is the potential for future damages, losses or casualties. A disaster event happens when a hazard event is combined with vulnerable inventory (that is when a hazard event strikes vulnerability inventory exposed to the hazard). The highest risk in a community occurs in high hazard areas (frequent and/or severe hazard events) with large inventories of vulnerable buildings or infrastructure. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-4

21 However, high risk can also occur with only moderately high hazard, if there is a large inventory of highly vulnerable inventory exposed to the hazard. For example, seismic hazard is lower in Oregon than in the seismically active areas of California. However, for some buildings, seismic risk in Oregon may be comparable to or even higher than seismic risk in California, because some of the building inventory in Oregon is much more vulnerable to earthquake damages. Conversely, a high hazard area can have relatively low risk if the inventory is resistant to damages (e.g., elevated to protect against flooding or strengthened to minimize earthquake damages) Mitigation Mitigation means actions to reduce the risk due to hazards. Mitigation actions reduce the potential for damages, losses, and casualties in future disaster events. Repair of buildings or infrastructure damaged in a disaster is not mitigation because repair simply restores a facility to its pre-disaster condition and does not reduce the potential for future damages, losses, or casualties. Hazard mitigation projects may be initiated proactively (before a disaster), or after a disaster has already occurred. In either case, the objective of mitigation is always is to reduce future damages, losses or casualties. A few of the most common types of mitigation projects are shown below in Table 1-1. Table 1-1: Examples of Common Mitigation Projects (Source: K. Goettel) Hazard Mitigation Project Build or improve levees or flood walls Improve channels for flood control Improve drainage systems and culvert capacities Flood Create detention ponds for storage Relocate, elevate or floodproof flood-prone structures Acquire and demolish highly flood-prone structures Add emergency generators for critical facilities Severe Storms Improve redundancy of utility systems Trim trees to reduce failures of utility lines Upgrade seismic performance of buildings Earthquakes Upgrade seismic performance of infrastructure Remediate slide conditions Landslides Relocate utility lines or structures Wildland/Urban Increase fire safe construction practices Interface Fires Vegetation (fuel load) control Enhance emergency planning and mutual aid General Expand public education programs The mitigation project list above is not comprehensive and mitigation projects can encompass a broad range of other actions to reduce future damages, losses, and casualties. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-5

22 1.5 The Mitigation Process The key element for all hazard mitigation projects is that they reduce risk. The benefits of a mitigation project are the reduction in risk (i.e., the avoided damages, losses, and casualties attributable to the mitigation project). In other words, benefits are simply the difference in expected damages, losses, and casualties before mitigation (as-is conditions) and after mitigation. These important concepts are illustrated below in Figure 1-3. Figure 1-3: Mitigation Projects Reduce Risk (Source: K. Goettel) RISK BEFORE MITIGATION BENEFITS OF MITIGATION RISK AFTER MITIGATION REDUCTION IN RISK Quantifying the benefits of a proposed mitigation project is an essential step in hazard mitigation planning and implementation. Only by quantifying benefits is it possible to compare the benefits and costs of mitigation to determine whether or not a particular project is worth doing (i.e., is economically feasible). Real world mitigation planning almost always involves choosing between a range of possible alternatives, often with varying costs and varying effectiveness in reducing risk. Quantitative risk assessment is centrally important to hazard mitigation planning. When the level of risk is high, the expected levels of damages and losses are likely to be unacceptable and mitigation actions have a high priority. Thus, the greater the risk, the greater the urgency of undertaking mitigation. Quantifying potential Mitigation Benefits is essential Greater the Risk, greater the Urgency for Mitigation Conversely, when risk is moderate both the urgency and the benefits of undertaking mitigation are reduced. It is neither technologically possible nor economically feasible to eliminate risk completely. Therefore, when levels of risk are low and/or the cost of mitigation is high relative to the level of risk, the risk may be deemed acceptable (or at least tolerable). Therefore, proposed mitigation projects that address low levels of risk or where the cost of the mitigation project is large relative to the level of risk are generally poor candidates for implementation. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-6

23 The overall mitigation planning process is outlined in Figure 1-4 below. It outlines the major steps in Hazard Mitigation Planning and Implementation for Sweet Home. Figure 1-4: The Mitigation Planning Process (Source: K. Goettel) Mitigation Planning Flowchart Risk Assessment Quantify the Threat to the Built Environment Is Level of Risk Acceptable? Risk Acceptable? Mitigation Not Necessary Risk Not Acceptable? Mitigation Desired Identify Mitigation Alternatives Find Solutions to Risk Prioritize Mitigation Alternatives Benefit-Cost Analysis and related tools Obtain Funding Implement Mitigation Measures Reduce Risk The first steps are quantitative evaluation of the hazards (frequency and severity) impacting Sweet Home and of the inventory (people, buildings, infrastructure) exposed to these hazards. Together these hazard and exposure data determine the level of risk for specific locations, buildings or facilities in Sweet Home. The next key step is to determine whether or not the level of risk posed by each of the hazards impacting Sweet Home is acceptable or tolerable. Only the residents of Sweet Home can make this determination. If the level of risk is deemed acceptable or at least tolerable, then mitigation actions are not necessary or at least not a high priority. Quantification of Hazards and Inventory at Risk Acceptability of Risk Levels City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-7

24 On the other hand, if the level of risk is deemed not acceptable or intolerable, then mitigation actions are desired. In this case, the mitigation planning process moves on to more detailed evaluation of specific mitigation alternatives, prioritization, funding and implementation of mitigation measures. As with the determination of whether or not the level of risk posed by each hazard is acceptable or not, decisions about which mitigation projects to undertake can be made only by the residents of Sweet Home. For reference, a more detailed discussion of the overall mitigation planning process, including each step in the planning process flow chart shown above in Figure 1-4, is given in Chapter 2 of the Regional All Hazard Mitigation Master Plan for Benton, Lane and Linn Counties (in both the Phase One and Phase Two reports) 1. Further, more detailed information for flood mitigation projects is given in Annex 1 of the Phase One Plan: Flood Hazard Mitigation Planning Template for Local Governments The Role of Benefit-Cost Analysis in Mitigation Planning Acceptability decisions made by residents of Sweet Home Communities, such as Sweet Home, that are considering whether or not to undertake mitigation projects must answer questions that do not always have obvious answers, such as: What is the nature of the hazard problem? How frequent and how severe are hazard events? Do we want to undertake mitigation measures? What mitigation measures are feasible, appropriate, and affordable? How do we prioritize between competing mitigation projects? Are our mitigation projects likely to be eligible for FEMA funding? Benefit-cost analysis is a powerful tool that can help communities provide solid, defensible answers to these difficult socio-political-economic-engineering questions. Benefit-cost analysis is required for all FEMA-funded Benefit-cost analysis mitigation projects, under both pre-disaster and post-disaster is required for all FEMAfunded mitigation mitigation programs. Thus, communities seeking FEMA funding must understand benefit-cost analysis. However, regardless of projects, under both whether or not FEMA funding is involved, benefit-cost analysis pre-disaster and postdisaster mitigation provides a sound basis for evaluating and prioritizing possible mitigation projects for any natural hazard. programs. Benefit-cost analysis software, technical manuals and a wide range of guidance documents are available from FEMA at no cost to communities. A Benefit-Cost Analysis Toolkit CD which contains all of the FEMA benefit-cost materials is available from FEMA. The publication What is a Benefit? Draft Guidance for Benefit-Cost Analysis is particularly recommended as a general reference for benefit-cost analysis. This publication includes categories of benefits to count for mitigation projects for various types of buildings, critical facilities, and infrastructure and has simple, standard methods to quantity the full range of benefits for most types of mitigation projects. 1 See the Regional All Hazard Mitigation Master Plan. Cascades West Council of Governments. Albany, Oregon. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-8

25 1.7 Hazard Synopsis To set the overall context of hazard mitigation planning, a brief review of the ten major hazards that impact Sweet Home is presented below. Some hazards affect the entire City, while some hazards have only localized potential impacts. The first six listed hazards may be primarily natural but 1-4 could have anthropogenic factors, either local (e.g., fire) or global factors. 1. Flooding: The City of Sweet Home has several areas of flood plains mapped by FEMA. These include areas along the South Santiam River, Taylor Creek, Ames Creek, and Wiley Creek. Of these areas, the mapped flood plain of Ames Creek contains the largest number of streets and structures and thus may be the most significant flood-prone area for Sweet Home. In addition, other portions of Sweet Home, outside of the mapped floodplains, are also subject to significant, repetitive flooding from local storm water drainage. 2. Severe Storms: The entire City of Sweet Home is subject to the effects of severe storms, including wind, rain, snow and ice, as well as secondary effects such as power outages. 3. Landslides: Portions of the hilly areas of Sweet Home are subject to landslides or mudslides, which affect buildings, roads, and utilities. 4. Wildland/Urban Interface Fires: The entire City of Sweet Home is subject to some level or risk from major wildland/urban interface fires. However, residential areas near the edge of Sweet Home, especially those bordering or impinging into forested areas have much higher levels of risk from wildland/urban interface fires. 5. Earthquakes: The entire City of Sweet Home is subject to the impacts of earthquakes, including not only major earthquakes on the Cascadia Subduction Zone off the Oregon coast, but also smaller crustal earthquakes within Oregon. 6. Volcanic Eruptions: The entire City of Sweet Home is subject to volcanic hazards from eruptions in the nearby Cascades Mountain Range, although the impacts are likely to be only very minor ash falls. 7. Dam Failures: Portions of Sweet Home along the South Santiam River are in the inundation areas from dam failures (in part, a technology-based hazard). While dam failures are highly unlikely, the consequences of failure would be high. 8. Disruption of Utility and Transportation Systems: The entire City of Sweet Home is subject to disruption or failures of utility and transportation systems (technology-based hazards) from severe storms and other natural hazards, as well as from anthropogenic causes. 9. Hazardous Materials: Additional technology-based hazards, such as hazardous material releases, are possible nearby or downwind from fixed site concentrations (e.g., industrial sites) as well as along transportation corridors from truck or railroad accidents. 10. Violence and Terrorism: Human-caused hazards include terrorist incidents or other deliberate malevolent actions by vandals, disturbed individuals or employees or members of organized groups could affect Sweet Home. These ten major hazards confronting Sweet Home are also recognized in the City s updated 2012 Emergency Operations Plan (EOP), as shown below in Tables 1-2, and 1-3. Table 1-2: Sweet Home Area Identified Threats/Hazards (Source: Sweet Home 2012 EOP, p. 2-4) Natural Technological Human-Caused 1. Floods 2. Severe Storms 3. Landslides 4. Wildland/Urban Interface Fires 5. Earthquakes 6. Volcanic Hazards 7. Dam Failure 8. Disruption of Utility and Transportation Systems 9. Hazardous Materials 10. Terrorism City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-9

26 Table 1-3: SWEET HOME AREA 2003 ALL HAZARD ANALYSIS MATRIX (Sorted by Total Risk) (Source: TCL Planning Consultants/Sweet Home City Staff and SH Fire & Ambulance District Staff Work Sessions December 2003) MAJOR HAZARD EVENT HISTORY (WF = 2) (Max Score = 20) VULNERABILITY (WF = 5) (Max Score = 50) MAXIMUM THREAT (WF = 10) (Max Score = 100) PROBABILITY (WF = 7) (Max Score = 70) TOTAL RISK (Max Score = 240) Severe Weather/Winter Storm Utility Failures (e.g., Electricity, Natural Gas, Communications) Water Supply Emergencies Flooding Earthquake Drought Wildland/Urban Interface Fire Hazardous Materials Emergency (HAZMAT) Infrastructure Failures (e.g., Bridge, Treatment Plant, Building Collapse) Volcano Eruption Epidemiological Event Dam Failure Urban Fire Transportation Accidents *Weapon of Mass Destruction (WMD) *Work/School Violence *Terrorism Landslide *Civil Disturbance Secondary Effects of Major Hazard Event in Region * Terrorism can include a wide variety of incidents, several of which were analyzed separately in the above matrix: Terrorism per se, Weapon of Mass Destruction (WMD), Work/School Violence, and Civil Disturbance. Note: This table is duplicated in Sweet Home s 2012 Emergency Operations Plan as Table 2-3 on page 2-6. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-10

27 In summary, there are many hazards which affect all or large portions of Sweet Home. Qualitative judgments on the relative level of risk and frequency of events for Sweet Home for each hazard are summarized below in Table 1-4. Table 1-4: Relative Risk and Frequency for Hazard Events (Source: K. Goettel) Hazard Relative Risk Frequency 1 Floods High High Winter Storms High High Earthquake High Low Landslides Moderate Moderate Wildland/Urban Fires Moderate Moderate Volcanic Hazards Low Low Dam Failures Low Low Disruption of Transportation/ Utilities High High Hazmat Incidents Low Moderate Terrorism Low Low 1 Low frequency or low probability doesn't necessarily mean low risk - an infrequent event such as a major earthquake can pose a high level of risk if the consequences are very high. Similarly, frequent events may pose low risk if the consequences are generally minor. High Frequency: small events may happen every year or two, with progressively larger events having progressively longer return periods. Moderate Frequency: small events may happen roughly every 5 to 25 years, with progressively larger events having progressively longer return periods. Low Frequency: significant events likely roughly every 50 years or longer, with progressively larger events having progressively longer return periods. 1.8 Outline of the Remainder of the SHMP The other chapters in this Mitigation Plan include the following: Chapter 2 provides a brief community profile for the City of Sweet Home. Chapter 3 documents the community involvement and public process involved in developing this mitigation plan. Chapter 4 outlines the plan goals, strategies, and action items. Chapter 5 documents the formal process of plan adoption, implementation, and maintenance. Chapters 6 through 15 cover each of the ten major hazards noted above and addressed in this mitigation plan, including: (Ch. 6) floods, (Ch. 7) severe storms, (Ch. 8) landslides, (Ch. 9) wildland/urban interface fires, (Ch. 10) earthquakes, (Ch. 11) volcanic hazards, (Ch. 12) Dam Failure, (Ch. 13) disruption of utility and transportation systems, (Ch. 14) hazmat incidents, and (Ch.15) terrorism. The Appendices include: Appendix 1: Summary of FEMA Mitigation Grant Programs Appendix 2: Principles of Benefit-Cost Analysis of Mitigation Projects. Benefit-cost analysis is required for most FEMA Mitigation Grant Applications and is a key factor in determining eligibility. Appendix 3: Community Involvement Documentation City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 1-11

28 2.1 Population and Demographics 2.0 COMMUNITY PROFILE: CITY OF SWEET HOME The City of Sweet Home has a population of over 9,025 (2012 population) and occupies 6.43 square miles along the South Santiam River in the foothills of the Cascades. Settlers first arrived in the Sweet Home Valley in 1851 and the City of Sweet Home was incorporated in Sweet Home s population grew slowly in the early years, until a demand for lumber created by the defense program in the 1940s transformed the town into a boom-town with logging operations starting throughout the area. In the 1980s, Sweet Home suffered economic and population declines as environmental issues and economic trends resulted in the closure of many sawmills and logging operations. The population of Sweet Home gradually declined to a low of 6,960 in In the 1990s, the City was revitalized with a combination of Federal grants for re-development and private investment and the population has steadily increased. The projected population in 2020 is 9,485 (Sweet Home Housing and Economic Analysis, 2001). Table 2-1: City of Sweet Home Demographic Profile (Source: 2010 Census) Age Under 5 years 7.1% Under 18 years 25.7% 18 years and over 74.3% 18 years to 65 years 57.6% 65 years and over 16.7% Ethnicity White 93.3% Black or African American 0.3% American Indian and Alaska Native 1.3% Asian 0.8% Native Hawaiian and Pacific Islander 0.1% Other or two or more races 4.1% Hispanic or Latino (of any race) 4.7% Note: the Age and Ethnicity categories above intentionally include overlapping subsets of categories for planning purposes. For emergency planning purposes, children, elderly adults, and people whose primary language is not English are generally considered special needs populations. Based on these census data, Sweet Home has a substantial population of children and elderly adults, with only a small population whose primary language is not English. As shown in Table 2-1 above, about 26% of the population of Sweet Home are children under 18 years old, while about 17% are adults over 65 years old. Only about 7% of the population is non-white and only about 5% is Hispanic. Most of Sweet Home is residential, with about 3,823 dwelling units, mostly single-family homes. Commercial and industrial development is concentrated mostly along the Highway 20 corridor. The assessment value of real estate in 2011 for the City of Sweet Home was $366,150,278, while the market value was $446,078,358. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 2-1

29 Public facilities in Sweet Home include nine parks, five schools, a library, police station, two fire stations, City Hall and other ancillary facilities. School enrollment in Sweet Home is about 2,303 (2011 data). Public infrastructure in Sweet Home includes miles of improved streets and 24 miles of unimproved streets, along with 5.60 miles of State Highways (Highways 20 and 228). The city-operated potable water system includes five reservoirs, a water treatment plant, 65 miles of water lines, and about 364 fire hydrants. The City-operated wastewater system includes a wastewater treatment plant and about 64 miles of wastewater lines. In addition to the City utilities, privately owned utility systems include electric power, natural gas, telecommunications and cable television. Total employment in Sweet Home is approximately 3,630 (2010 data). Employment in Sweet Home includes public entities such as the Sweet Home School District, the City of Sweet Home and the Sweet Home Fire and Ambulance District. The largest private employers are Weyerhaeuser, White s Electronics, and Safeway. Unemployment in Sweet Home has historically been somewhat higher than for Linn County as a whole, probably reflecting the long term effects of gradual declines in the timber industry. As of March 2013, the unemployment rate for Linn County was 11.4% the rate is Sweet Home runs normally higher. Unless otherwise referenced, the population and demographics data above are from the City of Sweet Home website: Geography and Climate Sweet Home is located on the south side of the South Santiam River, at the southeastern edge of the Willamette Valley, in the foothills of the Cascade Mountain range. Most of the City lies at elevations between 500 and 600 feet above sea level, with higher elevations in the hills at the southern edge of Sweet Home. In addition to the South Santiam River, there are several creeks running through Sweet Home, including Ames Creek, Taylor Creek, and Wiley Creek, and several smaller creeks. There are two large dams and reservoirs on the South Santiam River upstream from Sweet Home, the Foster and Green Peter Dams. The climate for Sweet Home is moderate with an average annual rainfall of 54 inches. Average monthly precipitation varies from about 8 inches in November through January to about 1 inch in July and August. Average annual snowfall is only about 1.4 inches. Mean daily temperatures range from highs of about 80 degrees and lows of about 50 degrees in July and August to highs of about 47degrees and lows of about 34 degrees in December and January. 2.3 Land and Development The Sweet Home Buildable Lands Inventory report (April 2007) contains data on zoning, land use and developable land in Sweet Home within the defined urban growth boundary. For Sweet Home, land within the city limits constitutes 95% of the land within the urban growth boundary. These data, which is the best data available, are summarized in the tables below, extracted verbatim from the 2007 report, prepared by the Community Planning Workshop (CPW), of the University of Oregon Community Service Center. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 2-2

30 Table 2-2 shows acres by designation in the Sweet Home Comprehensive Plan. Sweet Home has 3,521 acres, about 5.5 square miles, within the urban growth boundary. About 90% of the land within the urban growth boundary is in tax lots. For the purpose of the buildable lands inventory, any land outside of tax lots is considered committed and not available for development. Table 2-2: Acres by Comprehensive Plan Designation, Sweet Home Urban Growth Boundary (April 2007) Table 2-3 shows acreage in tax lots according to classification within the urban growth boundary. The inventory shows that 1,093 of the 3,175 acres (about 36%) in tax lots are developed. Another 918 acres fall within one or more constrained areas, leaving about 1,164 buildable (unconstrained) acres. Table 2-3: Buildable Acres in Tax Lots Sweet Home Urban Growth Boundary, April 2007 Table 2-4 shows acres in tax lots by Comprehensive Plan designation and land classification. There are 43 acres of potentially redevelopable land within the urban growth boundary, which is land that may, due to market forces, be redeveloped in the future. However, there is no way to guarantee when or if these tax lots will, in fact, be redeveloped. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 2-3

31 Table 2-4: Comprehensive Plan Land Designation and Classification Sweet Home Urban Growth Boundary, April 2007 Table 2-5 shows the buildable acres by Comprehensive Plan designation. The results shows that more than 1,100 acres of the 1,163 buildable acres are available for some type of housing (e.g., planned recreation commercial and residential). There are a much smaller number of buildable commercial or industrial acres, with 48 commercial and 22 industrial. Table 2-5: Buildable Acres by Comprehensive Plan Designation Sweet Home Urban Growth Boundary, April 2007 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 2-4

32 Map 2-1 shows the 2007 land use pattern in Sweet Home. This map is included for reference relative to the hazard maps shown in later chapters. Chapters 6 through 15 address the major hazards posing threats to Sweet Home. Many of these chapters include maps showing specific areas of Sweet Home where each hazard is significant. Map 2-1: Land Classification, Sweet Home Urban Growth Boundary, April 2007 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 2-5

33 2.4 Housing in Sweet Home The characteristics of the housing stock effects the level of risk posed by natural hazards. Table 2-6 identifies the types of housing most common throughout the city. Of particular interest are mobile homes and other non-permanent housing structures which account for 17 percent of housing in Sweet Home. Mobile structures are particularly vulnerable to certain natural hazards, such as windstorms, and special attention should be given to securing the structures as they are more prone to wind damage than wood-frame construction. Table 2-6: Sweet Home Housing Profile (2010) (Source: 2010 Census) Number of Housing Types Single-Family 2,666 70% Multi-Family % Mobile Homes % Van, RV, Boat, etc. 32 1% Total Housing Units 3,823 Percentage of Housing Types Age of housing is another characteristic that influences a structure s vulnerability to hazards. Generally, the older the home is, the greater the risk of damage. This is because stricter building codes have been developed following improved scientific understanding of plate tectonics and earthquake risk. In the Northwest, earthquake resistant designs and construction techniques were utilized in structures built after the 1960s. In the 1970s communities began implementing flood elevation ordinances that required homes in floodplains to be elevated to one foot above Base Flood Elevation. Oregon upgraded seismic standards to include earthquake loading in the building designs in the 1990s. Table 2-7 shows the age of housing stock across the City. Table 2-7: Housing Year Built (Source: U.S. Census Bureau, American Community Survey B25034 Year Structure Built) Structures Total Housing Units 3,934 Pre ,376 35% Percentage , % 1990 and Later 1, % City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 2-6

34 Knowing the age of the structure is helpful in targeting outreach regarding retrofitting and insurance for owners of older structures. Based on the U.S. Census data, 35 percent of the housing in Sweet Home was built prior to 1969 and the implementation of flood elevation requirements. There is a need to identify if these homes are located in a floodplain, and target outreach to the property owners to encourage appropriate flood mitigation. Roughly 38.6 percent of the housing units in the city were built after 1990 when more stringent building codes were put in place; an additional 26.4 percent of housing stock was built prior to current seismic standards. In addition to single-family households, it is also important to consider the structural integrity of multi-unit residences, as these structures will have an amplified impact on the population. In 2010, Sweet Home had 3,539 occupied housing units. Of the occupied housing units 65 percent (2,306) were owner occupied and 35 percent (1,233) renter occupied. Studies have shown that renters are less likely than homeowners to prepare for catastrophic events. Renters tend to have higher turnover rates that may limit their exposure to hazard information. Likewise, preparedness campaigns tend to pay less attention to renters. Renters typically have lower incomes and fewer resources to prepare for natural disasters, and renters may lack the motivation to invest in mitigation measures for a rented property. Table 2-6: Sweet Home Housing Data (2010) (Source: 2010 Census) Total Housing Units 3,823 Occupied 3,539 Vacant 284 Owner Occupied Units 2,306 Renter Occupied Units 1,233 Units in Structure 1 unit, detached 2,666 1 unit, attached 58 2 units 65 3 or 4 units to 9 units or more units 49 Manufactured Homes 628 Boat, RV, Van, etc. 32 Since 2009, changes to land use practices have decreased vulnerability in Sweet Home. Land use practices helped to limit hazard exposure by minimizing development in areas where the likelihood of hazard impact is high. For example, structures constructed in flood prone areas were sited outside of the floodplain whenever possible. In situations where structures had to be sited within floodplains property owner had to provide a certification by a registered professional civil engineer, that stated encroachments would not result in any increase in flood levels during the occurrence of the base flood discharge. Changes to building construction practices have also limited physical vulnerability by building structures whose resistance to hazard impacts is high. For example, structures constructed in flood prone areas are subject to flood resistant design and construction standards. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 2-7

35 3.0 Community Involvement and Public Process 3.1 Community Involvement in Sweet Home s Mitigation Planning The City of Sweet Home recognizes that community involvement is an essential step in developing and maintaining a mitigation plan. The City has involved the community throughout the mitigation planning process to help ensure that the final plan reflects the values and needs of residents, as well as building the support base necessary to implement the Plan. City staff started the 2015 update process early in 2013 by focusing on proofing, editing and updating the 2009 plan; these efforts continued in 2014 with assistance from TCL Planning Consultants. The 2015 Plan Update process was led by the City Manager, working directly with the City Department Directors and the Sweet Home Mitigation Planning Committee (SHMPC). In addition, each member of the City Staff Mitigation Team reviewed the entire Plan, analyzing each section for current accuracy. The City Staff Mitigation Team held a Kickoff Meeting on March 5, The Kickoff Meeting was followed by two Plan update meetings on March 18, 2014 and April 8, 2014 with the SHMPC and other community members. Agendas, meeting minutes, and presentation materials from these meetings can be found in Appendix 3 Community Involvement Documentation of this Plan. 3.2 Previous Mitigation Planning Activities Before 1996 Prior to the February flood of 1996, Sweet Home had no organized mitigation activities with the exception of the National Flood Insurance Program which identified the floodplains and flood ways within the City. The FIRM maps were effective as of March 1, 1982 and have been implemented through City code since that time. The City did have an Emergency Plan from 1981, but that Plan did not include any mitigation activities Post February 1996 Flood Event After the 1996 flood, the City participated in the Oregon Cascade West Council of Governments (Albany, Oregon) planning effort that resulted in the Regional All Hazard Mitigation Plan (RHAMP), Phases 1, 2, and 3. RHAMP - Phase 1 was completed in December of RHAMP Phase 2 was completed in May, And the final Phase, RHAMP Phase 3 was completed September Kenneth Goettel & Associates, Inc., was the consulting firm that helped the four county region create these documents. The Sweet Home City Council adopted Phases 1 and 2 on January 22, 2002 and Phase 3 on January 28, These multi-jurisdictional plans covered Linn County and Lane, Benton, and Lincoln counties. Sweet Home was one of the cities that took an active role throughout the process in helping create these four county regional plans Sweet Home Multi-Hazard Mitigation Master Plan The 2004 Sweet Home Multi-Hazard Mitigation Master Plan was developed under the lead of the Community Development Director, working directly with other City Department Directors and the Mitigation Planning Committee (SHMPC). Kenneth Goettel of Goettel & Associates, Inc. provided additional technical expertise during the plan development. The Plan was adopted by the City and approved by FEMA in The City has utilized the City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 3-1

36 activities identified in the Plan for projects during the five year period following its adoption. FEMA approved one mitigation grant request for a project expanding the floodplain area of Ames Creek. Other identified activities are ongoing as identified in Chapter The 2009 Update of the Sweet Home Multi-Hazard Mitigation Plan Sweet Home s Mitigation Planning Committee (SHMPC) played a lead role, along with City staff, in updating the Multi-Hazard Mitigation Plan in The first community meeting, held in March, 2009 included seventeen stakeholders and the public. After review by the SHMPC, the information gathered at the first meeting was incorporated into this Plan update. The Committee reviewed the final draft of the Plan, made suggestions and recommendations prior to the City Council s community meeting. A public meeting and presentation to the City Council to review the final draft of the Plan was held on April 28, The City Council subsequently adopted the revised plan, which was later accepted by FEMA. The 2009 updated plan is the basis for this 2015 updated plan. 3.3 A Brief History of the Sweet Home All Hazard Mitigation Planning Committee As a part of the RHAMP Phase 1 process, the City Council on August 27, 1996, passed a Resolution creating the All Hazard Mitigation Planning Committee (AHMPC). The creation of this group, now known as the Sweet Home Mitigation Planning Committee (SHMPC), recognized the importance of flood mitigation planning as a part of a comprehensive All Hazard Mitigation Plan for the City. The Council established the Committee as a permanent advisory body. Membership on the Committee includes a City staff person from Police, Public Works, and Planning and one staff person from the Sweet Home Ambulance and Fire District, with an equal number of citizen members. The term for membership is one year, appointed by the Mayor with approval of the Council. The first SHMPC focused on collecting data from the February 1996 flood. The survey work and compilation of data from this effort is discussed in Chapter 6 Floods. The Committee continued periodic meetings for the first year, and then became inactive. In April, 2003, the City reappointed the members of the SHMPC. The new members became very active in the preparation of the 2004 Plan. The Committee held one to two meetings per month from April to November of Members of the Committee had specific assignments, from gathering historic data to contacting community members. The background data the Committee collected has been used throughout this planning process, and carries over into the Emergency Operations Plan work that dovetails with this Plan. Hazard and risk information from the Mitigation Plan has been incorporated into hazard specific annexes of the Emergency Operations Plan. In addition to the normal meetings, the Committee participated in two large community meetings. The first meeting, held in July 2003, included all identified stakeholders and the public. The information gathered at this meeting was incorporated into the 2004 Plan. The second meeting, held in February 2004, included a presentation of the draft final plan for review and comment. As noted above in section 3.2.4, Sweet Home s Mitigation Planning Committee (SHMPC) played a lead role, along with City staff, in updating the Multi-Hazard Mitigation Plan in City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 3-2

37 Plan 1 Update Process The Sweet Home Mitigation Planning Committee (SHMPC) remains an active City Council committee. For the update process, the following citizens have been appointed to the SHMPC: Ned Kilpatrick, Scott LaRoque and Stephen Young. The other members of the SHMPC include Jeff Lynn, Sweet Home Police Chief, Mike Adams, Sweet Home Public Works Director, and Chief Mike Beaver, from the Sweet Home Fire and Ambulance and District. For the 2015 public portion of this update process, the City hosted: (1) a work session for City staff, Fire/Ambulance District (SHFAD) staff on March 5 th ; (2) a public work session for citizens, Planning Commission, City Council, the SHMPC, and City staff on March 18 th ; (3) a public work session for citizens, City Council, the SHMPC, and City staff on April 8 th ; and, (4) a public adoption of the updated plan by the City Council at a regularly scheduled City Council meeting on September 22, To ensure that the 2015 update of the Sweet Home Mitigation Plan has been prepared and reviewed by the key stakeholders within the community, the following process has been utilized. 1. The appointment of new members of the Sweet Home Mitigation Planning Committee. a. Recruitment of new members was done using notifications in the local media and personal contacts. b. The SHMPC staff members included the SHFAD Chief, Police Chief, Public Works Director, and City Manager 2. Materials to be reviewed in upcoming meetings were sent out in advanced for members to become acquainted with prior to meetings. 3. On March 18th, 2014 a public meeting for citizens, Planning Commission, City Council, and the SHMPC, was held to discuss the specific goals, mitigation strategies, and actions in the Plan. a. The agenda for the meeting included I. Review of the hazards potentially impacting Sweet Home (SHMP Chapters 1, 6-15), II. An overview of hazard mitigation planning (SHMP Chapter 1), III. Review of the SHMP Goals (SHMP Chapter 4) and IV. Discussion of potential mitigation projects to address the identified problems (SHMP Chapter 4). b. The attendees included Sweet Home City Manager, Sweet Home Mayor, three Sweet Home City Councilors, four Sweet Home Planning Commissioner s, and six SHMPC members. 4. A second public meeting for citizens, City Council, and the SHMPC, was held on April 8, The agenda was the same as the first public meeting, and included results of the first public meeting. 5. On April 14, 2015 hyperlinks to the draft plan were provided on the City webpage, inviting public comment on the draft. SHMPC members and the general public reviewed and commented on the draft plan during the period of April 14, 2015 to May 4, No comments received during the comment period. a. On September 22, 2015 a public presentation was made to the City Council to review the final draft of the Plan. Notification of this meeting included 1 The Sweet Home Multi-Hazard Mitigation Plan is now known as the Sweet Home Mitigation Plan (SHMP). City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 3-3

38 the same stakeholders and attendees from the two public meetings noted above. b. The agenda for the meeting included: I. A presentation of the Final Draft of the 2015 Update of the Sweet Home Mitigation Plan, II. Discussion of action items, III. Consideration of Adoption of the Plan with any specified revisions. 6. On September 22, 2015 the City Council adopted by resolution the 2015 updated Plan Changes Made to the 2009 SHMP in the 2015 Updated SHMP The entire document has been proofed and edited for clarity and grammatical correctness. Table 3-1 describes the substantive changes made to the 2009 Plan for the 2015 Update. Table 3-1: Substantive Changes made to the 2009 Plan for the 2015 Update (For detailed changes in Mitigation Action Items, see Table 4-1, page 4-4 in Chapter 4.) Chapter Section Substantive Changes Acknowledgements Adopt Resolution xxxxxxx xxxxxxx Acknowledgment added Copy of Signed Resolution of Adoption (by City Council) moved from end of Chapter 5 Executive Sum Table of Cont. xxxxxxx xxxxxxx Executive Summary updated Table of Contents updated Added Subsection titles and new Figure 1-1 (page 1-3) and 1-2 (page 1-4) Hazard cross indexing added ( Mitigation Plan with 2012 EOP) Section # & title added outline of the rest of the document Updated demographic information with 2010 and 2011 data Update housing data to 2010 and 2012 data New subsection 3.1 (Overview) & other subsections re-numbered; Updated information on public process, including participation and notifications Updated information and subsection tiles added: pre-1996, 1996 & following; 2009 update process Updated the Sweet Home Mitigation Planning Committee (SHMPC) information Updated the process information Updated change tracking for 2015 Plan Updated Resources and References Refined Objectives Clarification in wording of Goal 4, and Objectives A & B for Goal 6 (page 4-3) Updated Mitigation Action Items (see Table 4-1) 4 Table 4-2 Multi-Hazard: Table updated, modified to more directly represent Plan Goals 4 Table 4-3 Flood - inside FEMA Mapped floodplain: Table updated, modified to more directly represent Plan Goals 4 Table 4-3 Flood - outside FEMA Mapped floodplain: Table updated, modified to more directly represent Plan Goals 4 Table 4-4 Severe Storm: Table updated, modified to more directly represent Plan Goals 4 Table 4-5 Landslide: Table updated, modified to more directly represent Plan Goals 4 Table 4-6 Wildland/Urban Interface Fire: Table updated, modified to more directly represent Plan Goals 4 Table 4-7 Earthquake: Table updated, modified to more directly represent Plan Goals 4 Table 4-8 Volcanic Hazards: Table updated, modified to more directly represent Plan Goals 4 Table 4-9 Dam Failure: Table updated, modified to more directly represent Plan Goals 4 Table 4-10 Utility - Transportation: Table updated, modified to more directly represent Plan Goals 4 Table 4-11 Hazmat: Table updated, modified to more directly represent Plan Goals 4 Table 4-11 Terrorism: Table updated, modified to more directly represent Plan Goals Updated adoption information Added information on process for updating existing mechanisms Added information: completed South Santiam Watershed Council project (Ames Creek) City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 3-4

39 Table 3-1: Substantive Changes made to the 2009 Plan for the 2015 Update (For detailed changes in Mitigation Action Items, see Table 4-1, page 4-4 in Chapter 4.) Chapter Section Substantive Changes Updated maintenance schedule (summarized in Table 5-2, on page 5-6) Updated date of the Sweet Home Flood Insurance Study Updated information on the Flood Insurance Rate Map designations Updated information from the Flood Insurance Rate Map Updates events since Updated the number of policies in the NFIP in Table 6-2 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] 7 New Now titled Severe Storms. Previously this chapter had been entitled Winter Storms, but has been Chapter renamed in recognition of the fact that although severe storms are more likely to occur in the winter Title months, they can occur during any season of the year Updated tornado information Updated web page information Subsections & (page 7-6) added (updates events since 2009) 7 Table 7-5 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Inserted update to Subsections renumbered as 8.4 and Table 8-2 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Subsection 9.1 Overview title inserted All subsections renumbered Updated NFPA data to Updated NFPA data to Updated data to Added Sweet Home Fire and Ambulance District Data for Inserted update to Subsection renumbered as Table 9-8 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Subsections renumbered Added information on earthquake events since Updated information on water treatment plant 10 Table 10-6 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Added information on volcanic events since Subsections renumbered. 11 Table 11-4 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] 12 Title Title of Chapter and Hazard changed from Dam Safety to Dam Failures Added information on dam events since Subsections renumbered Subsection # 12.8 added for References 12 Table 12-7 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Introductory paragraphs given subsection # Subsections renumbered Removed Sweet Home airport which has officially been closed City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 3-5

40 Table 3-1: Substantive Changes made to the 2009 Plan for the 2015 Update (For detailed changes in Mitigation Action Items, see Table 4-1, page 4-4 in Chapter 4.) Chapter Section Substantive Changes Updated information on transportation or utility disruption events since Table 13-3 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Updated information to remove Sweet Home water treatment plant on 9 th Avenue Updated information on hazmat events since Renumbered as subsection Subsection # added for References Cited in this Chapter 14 Table 14-7 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Updated information on terrorism events since Renumbered as subsection Table 15-3 Table modified to more directly represent Plan Goals [Mitigation Action Items updated] Resources and References The following is not intended to be a full listing of resources used to create this plan. The references are provided in the order the information appears in the Chapter to meet the 2009 FEMA Reviewers Comments for the Local Hazard Mitigation Plan Review Crosswalk. Recommended Revision #4E (2009), which suggested a summary of the documents used in preparation of the Plan and the information used from each document. The information from each source is relatively obvious from the Chapter in which it was used and cited. Recognizing the importance of this FEMA suggestion, this format is retained in Chapter 1 (Introduction): $ Regional All Hazard Mitigation Master Plan for Benton, Lane Linn and Lincoln Counties. Kenneth Goettel & Associates Cascades West Council of Governments. Albany, Oregon. $ Flood Hazard Mitigation Planning Template for Local Governments. Kenneth Goettel & Associates Cascades West Council of Governments. Albany, Oregon. $ FEMA - What is a Benefit? Draft Guidance for Benefit-Cost Analysis. Chapter 2 (Community Profile): $ Census Research Institute, Portland State University. Chapter 4 (Mission Statement, Goals, Objectives, and Actions): $ Linn County Community Wildfire Plan. $ Oregon State Fire Marshall s Right to Know. Chapter 5 (Plan Adoption, Maintenance, and Implementation): $ Sweet Home Storm Water Master Plan. $ Sweet Home Comprehensive Plan. $ Sweet Home Building Codes. $ FIRM Maps. $ Sweet Home 2014 Strategic Plan. Chapter 6 (Flood Hazards): $ FEMA Flood Insurance Study for the City of Sweet Home (9-1-81). $ Sweet Home 1996 Flood Damage Survey. $ FEMA Flood Insurance Rate Maps. $ FEMA National Flood Insurance Program (NFIP). $ FEMA - What is a Benefit? Draft Guidance for Benefit-Cost Analysis. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 3-6

41 Chapter 7 (Severe Storms): $ Foster Dam Weather Station data. $ George Taylor, Oregon State Climatologist - Orographic Modeling. $ Wantz and Sinclair, Distribution of Extreme Wind Speeds in the Bonneville Power Administration Service Area, Journal of Applied Meteorology. $ National Weather Service - Portland Office. $ Wolf Read, Oregon State University. $ February Flood of 1996: A Regional Flood Recover Plan for Benton, Lane, Lincoln, and Linn Counties. November Oregon Cascades West Council of Governments. Chapter 9 (Wildland/Urban Interface Fires): $ Oregon Department of Forestry $ Mike Beaver, Chief, Sweet Home Fire and Ambulance District $ United States Forest Service. $ National Fire Protection Association (NFPA) Firewise Construction Checklist. $ NFPA Firewise Landscaping Checklist. Chapter 10 (Earthquakes): $ Regional Mitigation Plan, Phase Two Technical Appendix, Benton, Lane and Linn Counties Oregon, Seismic Loss Potential (2001). K. Goettle & Associates. Cascades West Council of Governments (Albany, Oregon). $ United States Geological Survey (USGS) - Seismic Hazard Maps for Oregon. $ Smithsonian Institution - Global Volcanism Project. $ USGS - Cascades Volcano. $ Department of Oregon Geology and Mineral Industries (DOGAMI). $ USGS - Volcano Hazards in the Three Sisters Region, Oregon. Chapter 12 (Dam Failures): $ National Inventory of Dams (NID), US Army Corps of Engineers. $ FEMA - Dam Safety: An Owner s Guidance Manual. $ National Research Council. $ NID Potential Hazard Categories. $ Oregon Emergency Management Division report of Dam/Levee Failure. $ Army Corps of Engineers, Portland District, Geotechnical Engineer Branch Concrete and Dam Safety Section. $ Army Corps of Engineers - Engineer Manual ( ). $ Green Peter Dam Emergency Plan (9-1981). Listed References from Chapter 12: FEMA, Federal Guidelines for Dam Safety: Hazard Potential Classification Systems for Dams, FEMA 333, October FEMA, Multihazard Identification and Risk Assessment, A Cornerstone of the National Mitigation Strategy, Chapter 20, Dam Failures, FEMA, Dam Safety: An Owner s Guidance Manual, FEMA 145, August National Research Council, Safety of Existing Dams, Evaluation and Improvement, National Academy Press, FEMA website ( National Dam Safety Program webpage. Oregon Emergency Management Division, Dam/Levee Failure, Statewide Hazard Analysis, March, Hills Creek Lake Project, Emergency Response Flowchart, Distributed January 2000, United States Army Corps of Engineers, Portland District, 5 pages. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 3-7

42 Chapter 13 (Disruption of Utility and Transportation Systems): $ FEMA - What is a Benefit (2001). $ American Society of Civil Engineers - Guidelines for the Seismic Upgrade of Existing Water Transmission Facilities (1999). $ Bonneville Power Administration (BPA). Chapter 14 (Hazardous Materials): $ Handbook of Chemical Hazard Analysis. $ Oregon Office of State Fire Marshal - Standard Operating Guidelines. $ Clean Air Act Amendments. $ Oregon Office of State Fire Marshal - Hazardous Substance Information System. $ Oregon Department of Transportation. $ Albany & Eastern Railroad. $ Burlington Northern and Santa Fe Railroad. Listed References from Chapter 14: Handbook of Chemical Analysis Procedures, Federal Emergency Management Agency, U.S. Department of Transportation, and U.S. Environmental Protection Agency, U.S. Government Printing Office, Emergency Response Guidebook (A Guidebook for First Responders During the Initial Phase of a Dangerous Goods/Hazardous Material Incident), developed jointly by the U.S. Department of Transportation, Transport Canada, and the Secretariat of Transport and Communications of Mexico, Hazardous Materials Emergency Response Teams Standard Operating Guidelines, May 7, 2001 Office of State Fire Marshal (Oregon). This series of about a dozen standard operating guidelines covers every main aspect of emergency response and recovery, including decisions to respond, levels of response, general response guidelines, mitigation methods, decontamination procedures, personal protective equipment, and others. Hazardous Substance Information System (HSIS), Office of State Fire Marshall, Version 1.3P, March Microsoft Access Database on CD-ROM. Annual Report of Hazardous Materials Incidents in Oregon as Reported by Oregon Fire Service, Office of State Fire Marshal (Oregon), 2000 and earlier years Milepost Inventory Update Form, Burlington Northern & Santa Fe Railroad, April 30, City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 3-8

43 4.1 Overview 4.0 MISSION STATEMENT, GOALS, OBJECTIVES and ACTION ITEMS The overall purpose of the Sweet Home Mitigation Plan is to reduce the impacts of future natural or human-caused disasters on Sweet Home. That is, the purpose is to make Sweet Home more disaster resistant and disaster resilient, by reducing the vulnerability to disasters and enhancing the capability of the City and its citizens to respond effectively to and recover quickly from future disasters. Completely eliminating the risk of future disasters in Sweet Home is neither technologically possible nor economically feasible. However, substantially reducing the negative impacts of future disasters is achievable with the adoption of this pragmatic hazard mitigation plan and ongoing implementation of risk reducing action items. Incorporating risk reduction strategies and action items into Sweet Home s existing programs and decision making processes will facilitate moving Sweet Home toward a safer and more disaster resistant future. This mitigation plan provides the framework and guidance for both short- and long-term proactive steps that can be taken to: Protect life safety, Reduce property damage, Minimize economic losses and disruption, Shorten the recovery period from future disasters, and Protect the environment. The Sweet Home Mitigation Plan is also intended to meet or support the regulatory requirements, including: FEMA s (Federal Emergency Management Agency) mitigation planning requirements so that Sweet Home remains eligible for pre- and post-disaster mitigation funding from FEMA, FEMA s Flood Insurance Program s Community Rating System guidelines, to help minimize future flood insurance rates in Sweet Home, Oregon Military Department, Office of Emergency Management s (OEM) mitigation planning evaluation criteria, and Oregon s Statewide Planning Goal 7 natural hazard planning guidelines. 4.2 Four-Step Mitigation Planning Framework The Sweet Home Mitigation Plan is based on a four-step framework that is designed to help focus attention and action on successful mitigation strategies: Mission Statement, Goals, Objectives and Action Items. Mission Statement. The Mission Statement states the purpose and defines the primary function of the Sweet Home Mitigation Plan. The Mission Statement is an action-oriented summary that answers the question Why develop a hazard mitigation plan? Goals. Goals identify priorities and specify how Sweet Home intends to work toward reducing the risks from natural and human-caused hazards. The Goals represent the guiding principles toward which the community s efforts are directed. Goals provide focus for the more specific issues, recommendations and actions addressed in Objectives and Action Items. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-1

44 Objectives. Each Goal has Objectives which specify the directions, methods, processes, or steps necessary to accomplish the plan s Goals. Objectives then lead directly to specific Action Items. Action Items. Action items are specific well-defined activities or projects that work to reduce risk. That is, the Action Items represent the steps necessary to achieve the Mission Statement, Goals and Objectives. 4.3 Mission Statement The mission of the Sweet Home Mitigation Plan is to: Proactively facilitate and support community-wide policies, practices, and programs that make Sweet Home more disaster resistant and disaster resilient. Making Sweet Home more disaster resistant and disaster resilient means taking proactive steps and actions to: Protect life safety, Reduce property damage, Minimize economic losses and disruption, Shorten the recovery period from future disasters, and Protect the environment. This hazard mitigation plan documents Sweet Home s commitment to promote sound public policies designed to protect citizens, critical facilities, infrastructure, private property and the environment from natural hazards by increasing public awareness, identifying resources for risk assessment, risk reduction and loss reduction, and identifying specific activities to help make Sweet Home more disaster resistant and disaster resilient. 4.4 Mitigation Plan Goals and Objectives Mitigation plan goals and objectives guide the direction of future policies and activities aimed at reducing risk and preventing loss from disaster events. The goals and objectives listed here serve as guideposts and checklists as the city, other agencies, businesses and individuals begin implementing mitigation action items within Sweet Home. The Sweet Home Mitigation Plan goals and objectives are based broadly on and consistent with the goals established by the State of Oregon Hazard Mitigation Plan. However, the specific priorities, emphasis and language are Sweet Home s. These goals were originally developed with extensive input and priority setting by the Sweet Home Mitigation Planning Committee (SHMPC) and the other stakeholders and citizens of Sweet Home. Goal 1: Reduce the Threat to Life Safety Objectives: A. Enhance life safety by minimizing the potential for deaths and injuries in future disaster events. B. Enhance life safety by improving public awareness of earthquakes and other natural hazards posing life safety risk to the Sweet Home community. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-2

45 Goal 2: Reduce the Threats to Sweet Home Buildings, Facilities and Infrastructure Objectives: A. Identify buildings and infrastructure at high risk from one or more hazards. B. Conduct risk assessments for critical buildings, facilities and infrastructure at high risk to determine cost effective mitigation actions to eliminate or reduce risk. C. Implement mitigation measures for buildings, facilities and infrastructure which pose an unacceptable level of risk. D. Ensure that new buildings and infrastructure in Sweet Home are adequately designed and located to minimize damages in future disaster events. Goal 3: Enhance Emergency Response Capability, Emergency Planning and Post- Disaster Recovery Objectives: A. Ensure that critical facilities and critical infrastructure are capable of withstanding disaster events with minimal damages and loss of function. B. Enhance emergency planning to facilitate effective response and recovery from future disaster events. C. Increase collaboration and coordination between Sweet Home, nearby communities, utilities, businesses and citizens to ensure the availability of adequate emergency and essential services for the Sweet Home community during and after disaster events. Goal 4: Seek Funding Sources for Mitigation Actions Objectives: A. Prioritize and fund action items with the specific objective of maximizing mitigation, response and recovery resources. B. Explore both public (local, state and federal) funding and private sources for mitigation actions. Goal 5: Increase Public Awareness of Natural Hazards and Enhance Education and Outreach Efforts Objectives: A. Develop and implement education and outreach programs to increase public awareness of the risks from natural hazards B. Provide information on resources, tools, partnership opportunities and funding resource sources to assist the community in implementing mitigation activities. C. Strengthen communication and coordinate participation among and within public agencies, non-profit organizations, business, industry and the public to encourage and facilitate mitigation actions. Goal 6: Incorporate Mitigation Planning into Natural Resource Management and Land Use Planning Objectives: A. Protect Sweet Home s sources of potable water. B. Balance natural resource management, land use planning, and natural hazard mitigation to protect life, property and the environment. C. Preserve, rehabilitate, and enhance environmentally sensitive areas and natural systems within Sweet Home to both enhance habitats and serve natural hazard mitigation functions. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-3

46 4.5 Sweet Home Mitigation Plan Action Items The Mission Statement, Goals and Objectives for Sweet Home, as outlined above, are achieved via implementation of specific mitigation action items. Action items may include refinement of policies, data collection to better characterize hazards or risk, education, outreach or partnership-building activities, as well as specific engineering or construction measures to reduce risk from one or more hazards to specific buildings, facilities, or infrastructure within the Sweet Home community. Many of the high priority action items focus on facilities which are critical or essential for Sweet Home. Critical facilities are facilities necessary for emergency response and recovery activities, especially public safety and hospitals. Essential utility services such as electric power, water and wastewater are also extremely important to communities, especially after a disaster. Such utilities are often characterized as lifeline utilities because they are so important to a community for life safety (e.g., services to hospitals) and for the economic recovery after a disaster. For Sweet Home, critical and essential facilities include City Hall, the Community Center, schools, the Fire Station, and the water, wastewater and stormwater systems Action Item Changes Since 2009 Table 4-1: Action Item Changes from the 2009 Plan to the 2015 Plan (MAI = Mitigation Action Item; ST = Short Term; LT = Long Term; CFs = Critical Facilities) MAI # MAI Brief Description Change Table 4-2: Multi-Hazard MAI (Chapter 4, page 4-6) ST 3 Neighborhood self-help groups for hazard emergencies. Reworded for clarity. ST 4 Access needs of emergency shelters. Reworded for clarity. ST 5 Preparedness programs Reworded for clarity. ST 6 Public/private partnership for mitigation Reworded for clarity. ST 7 City Web Page for emergency preparedness information for public. NEW LT 3 Neighborhood emergency self-help groups Reworded for clarity. LT 4 Integrate SHMP findings into City planning/regulatory documents Reworded for clarity. LT 5 Information for neighborhoods during emergencies. Delete Replaced by ST 7 Table 4-3: Flood MAI (Chapter 4, p. 6-14)/Same as Table 6-2 (Chapter 6, p.6-14) ST 1 FEMA Mapped: Update of 1982 FIS for Sweet Home. Completed in 2010, thus deleted. ST 1 Begin land use code changes vis-à-vis storage in flood plains. NEW LT 2 Outside FEMA Maps: Fund storm water treatment project. Completed and therefore deleted. Table 4-4: Severe Storm MAI (Chapter 4, p. 4-8)/Same as Table 7-5 (Chapter 7, p. 7-10) ST 1 Assess needs for generators in emergency shelters Split & reworded from old ST#.1 ST 2 Accessing vulnerable population within SH. Coordinating organizations changed. LT 3 Evaluate feasibility of solar/wind powered radios, etc. Completed - Not Viable deleted. LT 3 Continuing addressing back-up generator needs for City CFs Split & moved, clarified (old ST#1). LT 4 Tree trimming along main electrical lines Short term work completed, and the LT 5 Tree trimming along electrical lines to individual customers. ongoing maintenance moved to LT Table 4-5: Landslide MAI (Chapter 4, p. 4-9)/Same as Table 8-2 (Chapter 8, p. 8-7) ST 1 Design/implement mitigation project for specific slope areas. Completed and therefore deleted. ST 2 Inventory locations/structures subject to landslides. Completed and therefore deleted. ST 1 Implement Geo-tech work in previously identified slide areas. NEW Table 4-6: Wildland/Urban Interface Fire MAI (Chapter 4, p. 4-10)/Same as Table 9-8 (Chapter 9, p. 9-18) LT 2 Coordinate SH fire plans with Linn County, USFS and ODF. Completed and therefore deleted. LT 3 Road signage for evacuation routes. Evaluated - Not Viable deleted. LT 2 Continue fuels reduction projects & public education. ST completed, moved to LT (old ST1) City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-4

47 Continued Table 4-1: Action Item Changes from the 2009 Plan to the 2015 Plan (MAI = Mitigation Action Item; ST = Short Term; LT = Long Term; CFs = Critical Facilities) Table 4-7: Earthquake MAI (Chapter 4, p. 4-11)/Same as Table 10-6 (Chapter 10, p ) ST 1 Brief EQ Inventory of vulnerable important buildings. Reworded for clarity. Moved to LT #1. ST 2 EQ Inventory of vulnerable residential/commercial buildings. Reworded for clarity. Moved to LT #2. ST 3 FEMA pamphlets & public EQ awareness. Reworded for clarity. Renumbered ST#1. LT 1 Seek funding for retrofitting important buildings. Reworded for clarity. Renumbered LT#3. LT 2 Addresses CFs & Emergency Shelters. Reworded for clarity. Renumbered LT#4. Table 4-8: Volcanic Hazards MAI (Chapter 4, p. 4-12)/Same as Table 11-4 (Chapter 11, p. 11-7) ST 1 Update Public notification procedures for ash-falls. Completed and therefore deleted. ST 2 Update emergency response planning for ash-falls. (2012 EOP) Completed and therefore deleted. Table 4-9: Dam Failure MAI (Chapter 4, p. 4-12)/Same as Table 12-7 (Chapter 12, p ) xxx Tile of Table was Dam Safety but was changed to Dam Failure to accurately portray the hazard. ST 1 Part b: Public notification procedures & evacuation routes. Addressed & therefore deleted. ST 1 Part a: Obtain maps of dam failure inundation. Not completed and thus retained. Reworded for clarity. ST 3 Work with Linn Co call system for emergency response. Completed and therefore deleted. Table 4-10: Utility & Transportation System Disruption MAI (Chapter 4, p. 4-13)/ Same as Table 13-3 (Chapter 13, p ) ST 1 Addresses CFs & Emergency Shelters. Reworded for clarity. ST 3 Update emergency response plans. Completed and therefore deleted. ST 4 Red flag notification system. Addressed & therefore deleted. LT 1a Emergency potable water filling station. [Part of old LT 1] Split from LT 1 & reworded to clarify LT 1b Portable potable water source. [Part of old LT 1] Split from LT 1 & reworded to clarify LT 2 Enhanced communication/coordination with local ARES. Reworded for clarity. LT 3 Educate/encourage residents to stock emergency supplies moved to LT (old ST 2) LT 4 Increase fuel storage capacity for emergency backup New Table 4-11: HAZMAT Incident MAI (Chapter 4, p. 4-14)/Same as Table 14-7 (Chapter 14, p ) LT 1 Update site-specific lists of hazardous materials in SH (old ST1) Addressed in ST; reworded to clarify LT 2 Enhance emergency planning & agency coordination (old ST 2) Addressed in ST/moved to LT Table 4-12: Terrorism MAI (Chapter 4, p. 4-14)/Same as Table 15-3 (Chapter 15, p ) ST 2 Educational brochures for public awareness. Addressed in ST thus deleted. LT 1 Enhanced planning, coordination, training (old St 1) Addressed in ST/moved to LT/clarified LT 1 Update physical security & response water system [old LT 1] Completed therefore deleted. LT 2 Enhanced planning, training, equipment Reworded for clarity. Renumbered LT#1. LT 3 Enhanced security for other CFs. Reworded for clarity. Renumbered LT#2. Current action items identified and prioritized during the development of the Sweet Home Mitigation Plan are summarized in the following tables. Individual action items may address a single hazard (such as floods, or earthquakes) or they may address two or more hazards concurrently. The first group of action items that address more than one hazard, followed by groups of action items for each of the hazards considered in this plan, and addressed in detail in Chapters 6 to 15. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-5

48 OG OG OG OG 1 Yr OG OG OG 1-2 yrs OG 1-2 yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning ST #1 ST #2 ST #3 ST #4 ST #5 ST #6 ST #7 Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department SHFAD= Sweet Home Fire and Ambulance District; LCSC = Linn County Shelter Committee xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Multi-Hazard Mitigation Action Items Develop detailed inventories of at-risk buildings & infrastructure and refine priorities for mitigation actions. Identify and pursue funding opportunities to implement mitigation actions. Provide educational information to existing neighborhood groups to enable them to better help their close neighbors during hazard emergencies and to notify emergency response officials if assistance is needed. Work with Linn County Shelter Committee (LCSC), including Red Cross, to continually update Emergency Shelter Plans for the Sweet Home community. Include assessing needs especially for vulnerable populations (e.g., needs for generators in shelters). Identify, promote and make available personal preparedness programs for Sweet Home residents. Identify and promote public & private sector partnerships to foster hazard mitigation activities. Set up (and thereafter update and maintain) a City Web Page for emergency preparedness information and links for the public. Table 4-2: Multi-Hazard Mitigation Action Items CCDD CCDD; SHFAD SHMPC CCDD; LCSC; SHMPC SHMPC SHMPC CCDD; SHMPC Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 City X X X X X N/A X X X X X City X X X City, LCSC X X X City, Grant X X X City, Grant X X X X City X X LT #1 LT #2 LT #3 LT #4 Integrate hazard, vulnerability and risk Mitigation Plan findings into enhanced Emergency Operations planning. Continue the formal role for the SHMPC to maintain a sustainable process to encourage, implement, monitor, & evaluate city-wide mitigation actions. Identify and promote education programs for mitigating hazard risks. Integrate the Mitigation Plan findings into planning and regulatory documents and programs. EMC SHMPC SHMPC CCDD N/A X X X City X X X X City X X X City X X X X X Multi-Hazard Mitigation Action Items G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-6

49 OG OG OG OG 1-2 Yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 4-3: Flood Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Flood Mitigation Action Items Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 Flood Mitigation Action Items: Within Floodplains ST #1 Begin process of code revisions for storage in floodplains. CCDD City X X LT #1 LT #2 Survey elevation data for structures within the 100-yr floodplain, including coordination with Linn County Planning on use of LIDAR imaging for elevation information. For structures within the 100-year floodplain and especially for structures deep in the floodplain, explore mitigation options with property owners. CCDD CCDD Flood Mitigation Action Items: Outside Floodplains City City X X X X ST #1 Complete the inventory and mapping of locations in Sweet Home subject to frequent storm water flooding. CCDD City X LT #1 For locations with repetitive flooding and significant damages or road closures, determine and implement remedies. CPWD City X X X Duplicated as Table 6-2 in Chapter 6, page 6-14 G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-7

50 OG OG OG OG OG 1-2 Yrs 1-2 Yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning ST #1 Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; LCSC = Linn County Shelter Committee xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Severe Storm Mitigation Action Items Assess need for back-up power generators for emergency shelters in SH. Table 4-4: Severe Storm Mitigation Action Items SHMPC Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 City X X ST #2 Identify critical need locations, vulnerable populations, and vulnerable independent individuals. CCDD City X X X LT #1 Consider upgrading lines & poles to improve wind/ice loading, undergrounding critical lines, and adding interconnect switches to allow alternative feed paths and disconnect switches to minimize outage areas. Electrical Utility (PPL) PPL X X X LT #2 Encourage Pacific Power (PPL) to prioritize a coordinated emergency response (including enhanced communications) with City Public Works. CPWD; PPL PPL X X X LT #3 Assess needs for back-up power generators for all City-owned designated critical facilities and ensure that the highest priority critical facilities have generators or are wired to accept plug-in generators, as has been done for the waste water treatment plant (generator) and the new water treatment plant (wiring set up). Include assessing generator needs for City Hall and the Community Center. CPWD City X X X LT #4 Enhance tree trimming efforts especially for transmission lines and trunk distribution lines. PPL; CTC City, PPL X X X LT #5 Continue City-wide efforts encouraging property owners to keep trees trimmed near their electrical service drops. SHMPC; CTC City X X X X Duplicated as Table 7-5 in Chapter 7, page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-8

51 OG OG 1-2 yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built -Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 4-5: Landslide Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxx Landslide Mitigation Action Items Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 ST #1 Implementation of geo-tech work for new construction in previously identified areas subject to land slide. CPWD; CCDD City X X X X LT #1 Consider landslide mitigation actions for slides seriously threatening buildings or infrastructure. SHMPC; CPWD City X X X LT #2 Limit future development in high landslide potential areas. CCDD City X X X X X X Duplicated as Table 8-2 in Chapter 8, page 8-7 G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-9

52 OG OG OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built -Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning ST #1 LT #1 LT #2 Table 4-6: Wildland/Urban Interface Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Wildland/Urban Interface Mitigation Action Items Identify and map evacuation routes and procedures for high risk areas, disseminate and educate the public. Encourage fire-safe construction practices for existing and new construction in high risk areas. Continue fuels reduction projects and public education for the high hazard areas of SH identified previously. Initial work has been done, but continuing efforts necessary since fuels grow back. CE; SHPD; SHFAD; ODF SHMPC; CCDD; SHFAD; ODF SHFAD; ODF City, FEMA, ODF, SHFAD City, FEMA, ODF, SHFAD City, FEMA, ODF, SHFAD Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 X X X X X X X X X X X X Duplicated as Table 9-8 in Chapter 9, page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-10

53 OG 10 Yrs OG OG OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 4-7: Earthquake Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Earthquake Mitigation Action Items Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 ST #1 Obtain and make available to the public FEMA pamphlets to educate building owners and residents about structural and non-structural retrofitting of vulnerable homes and encourage retrofits. SHMPC City X X X LT #1 (1a) Complete inventory of important buildings, including schools, that may be particularly vulnerable to earthquake damage using FEMA s Rapid Visual Screening, (1b) and, as needed and as funding is available, conduct more detailed seismic vulnerability analysis of buildings which appear particularly vulnerable [*may require technical assistance from consultants]. CCDD, SH School District City, SH School District, FEMA X LT #2 Complete inventory of residential and commercial buildings that may be particularly vulnerable to earthquake damage, including pre-1940s homes, unreinforced masonry buildings, tilt-up buildings and buildings with soft first stories. [*May require technical assistance from consultants, and additional funding.] CCDD City, FEMA X LT #3 Seek funding to retrofit important public facilities with significant seismic vulnerabilities. CPWD City, FEMA X X X X X LT #4 Same as ST#4 in Table 4-2, and ST#1 and LT#3 in Table 4-4. (Addresses Critical Facilities and Emergency Shelters.) Same City X X X X Duplicated as Table 10-6 in Chapter 10, page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-11

54 OG 1-2 Yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning 1-2 Yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 4-8: Volcanic Hazards Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Volcanic Hazards Mitigation Action Items Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 ST #1 Evaluate capability of the new water treatment plant to deal with high turbidity from ash falls and upgrade emergency response plan to deal with ash falls. CPWD City X X Duplicated as Table 11-4 in Chapter 11, page G-1 G-2 G-3 G-4 G-5 G-6 Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Dam Failure Mitigation Action Items ST #1 ST #2 Obtain maps of dam failure inundation areas and update emergency response plan. Encourage US Corps of Engineers to complete seismic vulnerability assessments for Green Peter and Foster dams make seismic improvements as necessary. Table 4-9: Dam Failure Mitigation Action Items US Corps of Engineers; CCDD US Corps of Engineers; CCDD Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 USACE X X X USACE X X X Duplicated as Table 12-7 in Chapter 12, page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-12

55 1-2 Years OG 5 Yrs 5 Yrs 5 Yrs OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built -Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 4-10: Utility and Transportation System Disruption Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Utility and Transportation System Disruption Mitigation Action Items ST #1 LT #1a LT #1b LT #2 LT #3 LT #4 Same as ST#4 in Table 4-2, and ST#1 and LT#3 in Table 4-4. (Addresses Critical Facilities and Emergency Shelters.) Create an emergency potable water filling station. Obtain/have available a portable potable water source (e.g., tank truck, tender) for emergency water deliveries. Have a list of contact information and establish procedures for enhancing communications with and engaging the services of the Amateur Radio Emergency Services (ARES) in SH. Educate and encourage residents to maintain several days of emergency supplies for power outages or road closures. Increase the fuel storage capacity for emergency backup generator at wastewater treatment plant and reinstating fuel station at PW Maintenance Shops for City vehicles during emergencies. Same CPWD CPWD City; Linn Co. Emergency Services; ARES SHMPC CPWD Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 City X X X X City, FEMA X X X City X X X City, Linn County X X X X City X X X X City X X X Duplicated as Table 13-3 in Chapter 13 page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-13

56 OG OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning LT #1 LT #2 Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Hazmat Incident Mitigation Action Items Building on previous work, update site-specific knowledge of hazardous chemical inventories in SH including the State Fire Marshal s Community Right to Know lists so that first responders have readily available current information when needed. Enhance emergency planning, agency coordination, emergency response training and equipment to address hazardous materials incidents. Table 4-11: Hazmat Incident Mitigation Action Items SHAFD; SHPD SHAFD; SHPD Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 SHAFD, SHPD X X SHAFD, SHPD X X Duplicated as Table 14-7 in Chapter 14, page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-14

57 OG OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built -Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 4-12: Terrorism Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CFs = Critical Facilities; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx x Terrorism Mitigation Action Items Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 LT #1 Building on previous work, maintain enhanced emergency planning, agency coordination, emergency response training and equipment to address terrorism incidents. [ Terrorism can include a wide variety of incidents, several of which were analyzed separately in Table 1-3 (Chapter 1, page 1-10): Terrorism per se, Weapon of Mass Destruction (WMD), Work/School Violence, and Civil Disturbance.] SHPD; SHFAD SHAFD, SHPD X X LT #2 At City-owned and/or operated critical facilities, limit accessibility (e.g., fencing, walls) to (1) sensitive systems (e.g., HVAC) and (2) sensitive parts. Encourage School District to do likewise. [City has previously made considerable progress on its CFs.] CPWD; CCDD; School District; SHFAD City, SHAFD, SH School District X X Duplicated as Table 15-3 in Chapter 15, page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 4-15

58 5.0 Mitigation Plan Adoption, Implementation, and Maintenance 5.1 Overview For a hazard mitigation plan to be effective, it has to be implemented gradually over time, as resources become available, continually evaluated and periodically updated. Only through developing a system which routinely incorporates logical thinking about hazards and costeffective mitigation into ongoing public and private sector decision making will the mitigation action items in this document be accomplished effectively. The following sections describe how Sweet Home has adopted and will implement and maintain the vitality of the updated Sweet Home Mitigation Plan 5.2 Plan Adoption The Multi-Hazard Mitigation Plan, originally adopted by the Sweet Home City Council on March 9, 2004, was updated and adopted by Resolution on April 28, 2009, and again was updated and adopted by Resolution on September 22, A copy of the adoption resolution is located at the beginning of this document between Acknowledgements and the Executive Summary. The formal process of adoption included a presentation of the Plan to the City Council at a regularly scheduled meeting. The City Manager prepared a Request for Council Action which included a recommendation for the adoption of the Plan by the Sweet Home Mitigation Planning Committee (SHMPC). The Council adopted the Plan by Motion, with an immediate effective date. The Council adoption of the Plan by Council allowed for refinements as may be required by OEM and FEMA. Identified amendments have been incorporated into the adopted Plan. [Note: it would be best if FEMA approved the plan before Council action, but since one of FEMA s requirements is approval by Council this document in SHMP Section 5.4 below mandates local approval prior to submittal to FEMA.] The City has the necessary human resources to ensure that the Plan continues to be an actively used planning document. Over the years, the Council has been active in the preparation of the Regional and Sweet Home Mitigation plans, and has gained an understanding of not only the process, but also the importance of having a working mitigation plan. Since the flood of February 1996, the City has experienced a number of natural hazard events. These events have kept the importance of hazard mitigation alive at the Council level. 5.3 Implementation Implementation Through Existing Programs Implementing the Action Items identified in the Plan will engage the community. Public participation in the update of this Plan continues to build the network needed to be successful in implementation of the Plan. The City, with input from the SHMPC, will coordinate the implementation of the Plan. The City will continue to provide staffing for the SHMPC. Consistent staffing allows for well organized meetings and ensuring that the right people have been informed of the meetings and invited to attend the meetings. Implementation of the mitigation actions will be a series of community wide activities. Some projects can be done at the volunteer level, and others will require technical expertise. The stakeholders in the planning process will become project partners as needed on specific items. There are many organizations within the City that have common interests and City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 5-1

59 concerns, including hazard mitigation. Organizations such as the US Forest Service, Oregon Department of Forestry, Cascade Timber Consulting, South Santiam Watershed Council, Sweet Home Ambulance and Fire District, and the Sweet Home School District will continue to be important partners in the implementation of the Plan. To successfully complete action items will require project planning with active participation. Sweet Home has a long history and many examples of partnering with local, state, and federal agencies to complete both large and small projects. This experience will serve the community well with hazard mitigation projects. In addition, the City and other organizations within the City, have many existing programs that can be or should be linked with mitigation projects. A number of City documents have a relationship with various identified hazards. The City s Storm Water Master Plan covers the areas of the City with significant stormwater flooding identified in the Plan. The Storm Water Master Plan may also need to be updated in order to address additional areas identified in this Plan. In Oregon, with the rain received, the link between the two is obvious, and the projects of one will serve the intent of the other. As shown in Table 5-1, City Codes and Plans that have links to hazards. Table 5-1: City Codes and Plans with Linkages to Hazards Code or Plan Element Links Storm Water Master Plan Identifies storm water basins and regulates runoff Capital Improvement Plan Prioritizes fundable projects Sweet Home Local Wetlands and Riparian Identifies areas to protect for storm water Inventory retention and protection from slides SHMC* Chapter Erosion Control Prohibits erosion in sensitive areas and regulates erosion in areas with slopes, and into surface water SHMC Title 16 Land Division Requires consideration of flood zones, land stability concerns, riparian and wetlands SHMC Chapter Natural Resources Regulates activities in riparian zones and in significant wetlands * Sweet Home Municipal Code Integrating various plans and codes occurs primarily upon changes in any one of the documents. At the time of update to any of the above, lead staff prepares or has prepared the new documents. During this time, City processes include departmental review. At that time, if there are issues that should be integrated from the SHMP, it would be identified and language would be drafted and added or amended needed. All of the above Codes and Plans have public review requirements, as well as adoption requirements that would provide further review. During the updating process, other agencies and organizations will be encouraged to update their documents to include the new updates in this Plan that may impact their operations. The work on Ames Creek ( ) serves as prime example of how partnerships can achieve multiple objectives. Ames Creek runs through the core of Sweet Home. The Creek historically has been degraded, with not only changes to the flow of the channel, but filled in, dammed, and highly impacted with development. This resulted in the Creek being an eyesore that also contributed to local flooding. The banks have been resloped, the native riparian zone reestablished, the channel realigned in a couple of key areas, and one acre of degraded floodplain was reconnected and improved. The South Santiam Watershed Council completed improved connection of Ames Creek with the South Santiam River on the City of Sweet Home s land. The Ames Creek work aids in storm water conveyance while increasing fish passage, improving wildlife habitat and beautifying the community. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 5-2

60 The connection between plans will be true for other plans and projects within the City, including plans such as the City of Sweet Home s Comprehensive Plan and South Santiam Watershed Council s Santiam River Watershed Analysis and Plan [completed in 2000]. As development plans come into the Planning Office and the Building Inspection Program Office, reviewers will need to keep in mind potential hazard mitigation actions that may need to be implemented. The adopted Building Codes for the City include standards that mitigate potential hazard damage. The City stays current in adoption of upgraded codes, ensuring that the new construction activities will meet the highest standard available for hazards such as floods and seismic. A key Building Code element implements the NFIP by setting standards for construction within a 100 year floodplain. The consultants who currently act as the City s Building Official, as well as the City s building inspector (City staff) have completed the ATC- 45 Safety Evaluation of Buildings after Windstorms and Floods training. Building Inspectors are expected to complete this course to help them in the assessment of building safety after floods and also to understand the construction requirements within the regulated flood plain. The City s participation in this program provides property owners with the opportunity to get important insurance that will aid them in the event of a flood. The City provides floodplain information to the public on a regular basis. For the purpose of obtaining a Building Permit, properties that are within mapped 100 year floodplain areas on the FIRM maps must provide a FEMA Certification of Elevation. This information is kept both in the property files and in a special book that serves to track all permits issued within the 100 year floodplain, thus facilitating easy review of this information Cost Effectiveness of Mitigation Projects As Sweet Home and other entities, public or private, within the City consider whether or not to undertake specific mitigation projects or evaluate how to decide between competing mitigation projects, they must answer questions that don t always have obvious answers, such as: What is the nature of the hazard problem? How frequent and how severe are hazard events? Do we want to undertake mitigation measures? What mitigation measures are feasible, appropriate, and affordable? How do we prioritize between competing mitigation projects? Are our mitigation projects likely to be eligible for FEMA funding? Sweet Home recognizes that benefit-cost analysis is a powerful tool that can help communities provide solid, defensible answers to these difficult socio-political-economicengineering questions. Benefit-cost analysis is required for all FEMA-funded mitigation projects, under both pre-disaster and post-disaster mitigation programs. Thus, communities seeking FEMA funding must understand benefit-cost analysis. However, regardless of whether or not FEMA funding is involved, benefit-cost analysis provides a sound basis for evaluating and prioritizing possible mitigation projects for any natural hazard. Sweet Home will use benefit-cost analysis and related economic tools, such as cost-effectiveness evaluation, to the extent practicable in prioritizing and implementing mitigation actions. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 5-3

61 5.3.3 STAPLE/E Approach Sweet Home will also use the STAPLE/E to help evaluate potential mitigation actions. Using STAPLE/E criteria, mitigation activities can be evaluated quickly in a systematic fashion based on the Social, Technical, Administrative, Political, Legal, Economic, and Environmental (STAPLE/E) considerations and opportunities for implementing particular mitigation action items in the City. The STAPLE/E approach is helpful for doing a quick analysis of mitigation projects. Most projects that seek federal funding and others often require more detailed Benefit/Cost Analyses. The following are suggestions for Sweet Home to examine each aspect of the STAPLE/E Approach: Social: Planning Department staff, local non-profit organizations, or local planning groups can help answer these questions. Is the proposed action socially acceptable to the community? Are there equity issues involved that would mean that one segment of the community is treated unfairly? (Or one segment more favorably?) Will the action cause social disruption? Technical: Public Works, Engineering and Building Department staff can help answer these questions. Will the proposed action work? Will it create more problems than it solves? Does it solve a problem or only a symptom? Is it the most useful action in light of other goals? Administrative: Elected officials can help answer these questions. Is the action implementable? Is there someone to coordinate and lead the effort? Is there sufficient funding, staff, and technical support available? Are there ongoing administrative requirements that need to be met? Political: City Council members can help answer these questions. Is the action politically acceptable? Is there public support both to implement and to maintain the project? Legal: Include legal counsel, land use planners, and risk managers in this discussion. Who is authorized to implement the proposed action? Is there a clear legal basis or precedent for this activity? Are there legal side effects? Could the activity be construed as a taking? Is the proposed action allowed by the comprehensive plan, or must the comprehensive plan be amended to allow the proposed action? Will the City be liable for action or lack of action? Will the activity be challenged? City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 5-4

62 Economic: City staff, civil engineers, Building Department, Sweet Home Economic Development Group, and the County Assessment/Taxation office can help answer these questions. What are the costs and benefits of this action? Do the benefits exceed the costs? Are initial, maintenance, and administrative costs taken into account? Has funding been secured for the proposed action? If not, what are the potential funding sources (public, non-profit, and private)? How will this action affect the fiscal capability of the City? What burden will this action place on the tax base or economy? What are the budget and revenue effects of this activity? Does the action contribute to other goals, such as capital improvements or economic development? What benefits will the action provide? (This can include dollar amount of damages prevented, number of homes protected, credit under the CRS, potential for funding under the HMGP or the FMA program, etc.) Environmental: Environmental groups, land use planners, Engineering, and natural resource managers can help answer these questions. 5.4 Maintenance How will the action impact the environment? Will the action need environmental regulatory approvals? Will it meet local and state regulatory requirements? Are endangered or threatened species likely to be affected? The Sweet Home Mitigation Plan (or SHMP) will be monitored and evaluated on a regular basis as the community implements the action items within the Plan. The hazards that exist in the community will continue to exist, but the conditions within the community will continue to change. As these changes occur, the Plan needs to be reevaluated. This may be a change in the population or in the development patterns that were in place when the Plan was developed. Monitoring the Plan will provide information on how the actions set forth have met the needs of the community. The lead City staff 1 has the responsibility for monitoring the Planning process. On an annual basis, designated City staff will bring together the Sweet Home Mitigation Planning Committee (SHMPC) to monitor the Plan. During the monitoring process, the SHMPC may visit any active or completed mitigation sites. After the meeting, designated staff will prepare a report that highlights the year s activities to be used in the evaluation process. The annual report will also include synopses of any significant hazard events which occurred during the year. The monitoring process will lead into the evaluation of the Plan by the City, SHMPC, and other stakeholders identified within this Plan. The goals and objectives of the plan will be reviewed to ensure they remain current. The designated City staff will review and report on the identified resources for implementing the Plan. This evaluation provides the opportunity to include new information into the Plan and to note outdated items and completed actions. In reviewing Plan Actions, the SHMPC and City staff will evaluate the identified hazards 1 City staff and/or Department Head as designated the lead by the City Manager. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 5-5

63 within the Plan to access any changes to the risk the City has from each hazard. The evaluation process will be the time to recognize the success of the community in implementation of action items. The continuous monitoring and evaluation process will provide the designated City staff with the basic information needed to update the Plan. The designated City staff will incorporate information from the monitoring reports and evaluation process in a Draft Update of the Plan. After completion of this Draft Update, the SHMPC and the stakeholders will meet to review and analyze the Draft. Included within the review, the meeting agenda will include a basic SWOT analysis to assess changes in the City that impact implementation of the Plan. All proposed Actions will undergo the STAPLE/E approach discussed in Section The Draft Update will be refined after the meeting to make any desired changes. The SHMPC and stakeholders will be provided copies of the Updated Plan as it will be submitted to Council for their adoption prior to submittal to FEMA. The schedule for the monitoring, evaluation, and updating of the Plan shall have elements that are consistently timed and other elements that will occur based on hazard events. The schedule shown Table 5-2 will be utilized for this process. The months noted below are deadlines these meetings could take place earlier each year at the City Manager s discretion. Table 5-2: Proposed Schedule for Plan Maintenance Plan Element 1 st Year 2 nd Year 3 rd Year 4 th Year 5 th Year City Staff Mitigation Team Annual Review/Work Sessions* March March March March March Monitoring Meeting* May May May May January Evaluation Meeting* June June June June February Hazard Event Meetings As Needed As Needed As Needed As Needed As Needed Prepare Draft Update Ongoing Ongoing Ongoing Ongoing March Revised Draft Update May City Council Hearing June FEMA Submittal July * Denotes meetings that could take place simultaneously at the City Manager s discretion. Changes that may affect the effectiveness of the Plan could be changes in the values of the citizens of the City. Community values have be regularly monitored through Sweet Home s Strategic Plan update process. As the Strategic Plan is implemented, the Mitigation Plan may need to be reviewed as well. Beyond the Strategic Plan, Sweet Home citizens will be informed of implementation efforts through the local newspaper coverage and ongoing City Council meetings. City staff will work with the public on a regular basis. As many of the mitigation projects will affect citizens, staff will track comments and forward them to the appropriate people for input. The tools for participation in Sweet Home follow the traditional paths of small communities, which typically involve word of mouth and action rather than conducting more meetings. Keeping the Plan visible through ongoing implementation efforts will provide opportunities for news coverage. The New Era (local newspaper) does a good job providing information to the public and informing them of the correct City contacts for input. The listed contacts will be the appropriate staff for the mitigation effort. The listed contact information includes location of City offices, City phone numbers, and City . The designated City staff will continue to have the primary responsibility for ensuring the Plan continues to be monitored. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 5-6

64 As mitigation becomes more of a focus for Sweet Home residents, the Plan will be reviewed based on public input in order to keep it current. The City Council meetings have open agenda opportunities for the public to discuss items with the Council. Hazard projects, proposed and ongoing, will all be presented to Council in a number of formats. Most strategies have a fiscal impact on the City, and therefore they will be a part of the municipal budgeting process. The budget meetings are open to the public for comments about the resources projected towards projects. Hazard mitigation projects from the Plan will be discussed, which may lead to project completion or a need to review the Plan for updating. Local, state and federal agencies routinely conduct or refine studies that may lead to new or better information on specific hazards for the City. The new information will need to be incorporated into other documents, such as the Comprehensive Plan and this Mitigation Plan. For example, this could include updated flood plains, identification of landslide areas or areas subject to seismic vulnerability. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 5-7

65 6.1 Overview 6.0 FLOOD HAZARDS The City of Sweet Home is subject to flooding from several flood sources, including: 1) Over bank flooding from the South Santiam River 2) Over bank flooding from Ames, Taylor, and Wiley Creeks, and on smaller creeks such as Cotton and Stonebrook Creeks 3) Local storm water drainage flooding Major flooding events in Sweet Home generally result from large winter storms with intense rainfall, with flooding sometimes exacerbated by snow-melt runoff. These large winter storms often result in simultaneous flooding on all rivers and streams in an affected area. However, because of differences in drainage areas, slopes, and other watershed characteristics, the severity of flooding in any given rainfall event often varies significantly from stream to stream. 6.2 Historical Floods in Sweet Home Historically, flooding has occurred in the Sweet Home area throughout the recorded history of the area, since the first European settlers arrived in the mid-1800s. The FEMA Flood Insurance Study for the City of Sweet Home (September 29, 2010) has a brief history of major historical floods in the area. Major floods on the South Santiam River occurred in 1861, 1890, and 1964, with smaller, but substantial flood events in 1931 and The 1964 flood resulted in substantial flooding and damage to the City s water and wastewater treatment plants. In considering these past major floods on the South Santiam River, it is important to recognize that the construction of the Green Peter and Foster Dams, both operational in 1967, have substantially reduced flood potential on the South Santiam River. These two dams have reduced the expected 100-year stream discharge (volume of water flowing in the river) from 103,000 cubic feet per second to 44,000 cubic feet per second, measured at the Waterloo gage station downstream from Sweet Home. This substantial reduction in expected flood discharges is correspondingly reflected in substantial reductions in expected flood elevations and thus in overall flood potential for major flood events along the South Santiam River. Despite the reduction in flood potential from construction of the Green Peter and Foster Dams, the City of Sweet Home continues to have some flood risk from the South Santiam River as well as from the creeks running through Sweet Home. Flood risk on the creeks in Sweet Home is not affected by the dams on the South Santiam River. Historically, flooding on the South Santiam River has often been accompanied by flooding on Ames, Taylor, and Wiley Creeks as well as on smaller creeks in Sweet Home. Ames Creek has flooded numerous times, with major flood events in 1964, 1966, 1974, and Similarly, Taylor and Wiley Creeks have also flooded numerous times, albeit typically with less damage, because of limited development in the flood-prone areas adjacent to these creeks. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-1

66 6.2.1 The February 1996 Flood The most recent major flood event in Sweet Home occurred in February Unusually heavy rains over the four-day period from February 5 th to February 8 th resulted in major flooding on numerous rivers and streams throughout Oregon. At the peak of this flood event, access to Sweet Home was largely cut off because all of the major access roads were closed by flooding and/or mudslides, including Highway 20 both east and west of Sweet Home and Highway 228 to the southwest. During this rainfall event, Foster Dam reached capacity and Green Peter Dam nearly reached capacity. However, water flows released from these dams were well within design specifications for these dams. During the 1996 flood event, Sweet Home did not experience flooding from the South Santiam River. The upstream dams both performed as designed and limited discharges to levels low enough to avoid flooding in Sweet Home. However, Sweet Home did experience significant flooding from the numerous creeks running through the City, especially from Ames Creek. Over bank flooding from Ames Creek affected Sweet Home, including locations near the High School, Library, City Hall, Police Building, and Fire Hall as well as the center of the downtown district. Many businesses were affected along Main Street and Long Street. Emergency response functions were impacted by flooding of the Police Department and the Emergency Dispatch Center which were located in the basement of the City Hall building at the time of this flood event. In addition to overbank flooding from Ames Creek, several residential areas of Sweet Home suffered flood damages from localized storm water drainage problems. Portions of Sweet Home with significant flooding in the 1996 flood event are shown below on Map 6-1, the 1996 Flood Event. Figure 6-1 shows several representative photographs of flooding in Sweet Home during the 1996 flood event The 1998 Flood Flooding again in occurred Sweet Home on Thanksgiving Day, 1998, but this event was not nearly as severe as that of Localized flooding occurred in the vicinity of 18 th Avenue and Tamarack Street, as well as along Long Street between 35 th and 45 th Avenues and in the Airport Lane and Mahogany Street areas. These same areas flooded in 1996, as shown in Map 6-1 below Flood Events Since 2004 There have been no significant flood events in Sweet Home since completion of the first edition of the Sweet Home Multi-Hazard Plan in 2004, or since the 1998 flooding. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-2

67 Map 6-1: 1996 Flood Event City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-3

68 Figure 6-1: 1996 Flood: Representative Photos City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-4

69 6.3 Flood Hazards and Flood Risk: Within Mapped Floodplains Overview Flood prone areas of Sweet Home include National Flood Insurance Program (NFIP) mappedfloodplains for the South Santiam River, Ames Creek, Taylor Creek and Wiley Creek. According to the 1996 Flood Damage Survey (City of Sweet Home All Hazard Mitigation Committee), 232 properties in Sweet Home lie within the 100-year flood plain boundaries. These 100-year flood plain boundaries are shown in Map 6-2 and Map 6-3. These maps also show that there are relatively few properties in the 100-year flood plains of the South Santiam River, Taylor Creek and Wiley Creek. Most of the Sweet Home properties located within the 100-year flood plain are in the Ames Creek floodplain. Full details of these mapped floodplains are included on the two panels of the Flood Insurance Rate Maps (FIRMS) (Effective Date: September 29, 2012) that cover the City of Sweet Home, along with the accompanying Flood Insurance Study (September 29, 2012). For Sweet Home, the FIRMS include the following types of areas: 1. AE Zone replaced the numbered A Zones within the 100-year floodplain, with Base Flood Elevations determined. 2. A Zone replaced the unnumbered A zones within the 100-year floodplain, with no Base Flood Elevations determined. 3. X (shaded) Zone replaced the B Zone, areas of 0.2% annual chance flood with average depths of less than 1 foot or with drainage areas less than 1 square mile. 4. X (unshaded) Zone replaced Zone C, areas determined to be outside the 0.2% annual chance flood. The FEMA Flood Insurance Study and FIRMS for Sweet Home include a large number of acronyms. A good summary of the terms used in flood hazard mapping is available on the FEMA website at: and City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-5

70 Map 6-2: Flood Plains in Sweet Home City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-6

71 Map 6-3: Flood Plains in Downtown Area of Sweet Home City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-7

72 6.3.2 Flood Hazard Data For mapped floodplain areas, the flood hazard data included in the Flood Insurance Study (FIS) allow quantitative calculation of the frequency and severity of flooding for any property within the floodplain. For example, for the South Santiam River at the confluence of Wiley Creek, the NFIP FIS includes the following data: Table 6-1: Flood Hazard Data South Santiam River at Wiley Creek Flood Frequency Discharge Elevation (years) (cfs) (feet) 10 18, , , , The stream discharge data shown above are from the Table on Page 27 of the FIS Volume 1. These data are applicable to the entire reach of the South Santiam River through Sweet Home. Stream discharge means the volume of water flowing down the river and is typically measured in cubic feet of water per second (cfs). The flood elevation data are from the Flood Profile Graphs 57P and 58P in the FIS Volume 2. Flood elevation data vary with location along the reach of the river and thus separate flood elevation data points must be read from the graph at each location along the river. Quantitative flood hazard data such as shown above, are very important for mitigation planning purposes because they allow quantitative determination of the frequency and severity (i.e., depth) of flooding for any building or other facility (e.g., road or water treatment plant) for which elevation data exist. Such quantitative flood hazard data also facilitate detailed economic analysis (benefit-cost analysis) of mitigation projects to reduce the level of flood risk for a particular building or other facility. Further details and examples of how such data are used are given in the Appendix (Mitigation Project Examples) Caveats for the Sweet Home Flood Insurance Study The Flood Insurance Study (FIS) for Sweet Home was updated in 2010, as was anticipated in the 2009 Plan. However, the changes, especially on Ames Creek, that had been noted in the 2009 Plan did not occur. The only changes in the elevations resulted from the change from the NGVD 1029 datum to the North American Vertical Datum of No other changes based on past channel changes are reflected on the new maps Interpreting Flood Hazard Data for Mapped Floodplains The level of flood hazard (frequency and severity of flooding) is not determined simply by whether the footprint of a given structure is or is not within the 100-year floodplain. A common error is to assume that structures within the 100-year floodplain are at risk of flooding while structures outside of the 100-year floodplain are not. This simplistic view is simply not true. Some importance guidance for interpreting flood hazards is given below. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-8

73 A. Being in the 100-year floodplain does not mean that floods happen once every 100 years. Rather, a 100-year flood simply means that the probability of a flood to the 100-year level or greater has a 1% chance of happening every year. B. Within or near the 100-year floodplain, the key determinant of flood hazard for a building or other facility is the relationship of the elevation of the structure or facility to the flood elevations for various flood events. Thus, for example, homes with first floor elevations below or near the 10- year flood elevation have drastically higher levels of flood hazard than other homes with first floor elevations near the 50-year or 100-year flood elevations or at higher elevations. C. Much flooding happens outside of the mapped 100-year floodplain. First, the 100-year flood is by no means the worst possible flood. For flooding along the South Santiam River, the 500-year flood is more than 5 feet higher than the 100-year flood. Thus, floods greater than the 100-year event will flood many areas outside of the mapped 100-year floodplain. Second, many flood prone areas flood because of local storm water drainage conditions (see Section 6.4 below). Such flood prone areas have nothing to do with the 100-year floodplain boundaries. 6.4 Flood Hazards and Flood Risk: Outside of Mapped Floodplains Section 6.3 above applies only to the limited portions of Sweet Home that are within the mapped floodplains of the South Santiam River, Ames Creek, Taylor Creek, and Wiley Creek. Other portions of Sweet Home outside of the mapped floodplains are also at relatively high risk from over bank flooding from streams too small to be mapped by NFIP (e.g., Cotton Creek), or from local storm water drainage. Many areas of the United States including Oregon and Sweet Home -- outside of mapped floodplains are subject to repetitive, damaging floods from local storm water drainage. In most cities, storm water drainage systems are designed to handle only small to moderate size rainfall events. Storm water systems are sometimes designed to handle only 2-year or 5-year flood events, and are rarely designed to handle rainfall events greater than 10-year or 15-year events. For local rainfall events that exceed the collection and conveyance capacities of the storm water drainage system, some level of flooding inevitably occurs. In many cases, local storm water drainage systems are designed to allow minor street flooding to carry off storm waters that exceed the capacity of the storm water drainage system. In larger rainfall events, flooding may extend beyond streets to include yards. In major rainfall events, local storm water drainage flooding can also flood buildings. In extreme cases, local storm water drainage flooding can sometimes result in several feet of water in buildings, with correspondingly high damage levels. For most of Sweet Home, storm water drainage is facilitated by a system of drains and underground pipes which drain into the numerous creeks in Sweet Home and ultimately into the South Santiam River. In outlying areas, much of the storm water drainage system is open channels. Many of these are located on private property, which often makes maintenance of capacity more difficult than for those located within public right-of-ways. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-9

74 In the residential zones in the west half of Sweet Home, about half of the drainage system has adequate capacity and about half is undersized. In the east half of Sweet Home, the culverts crossing Main Street are generally adequate but many street crossing culverts in residential areas both north and south of Main Street are undersized by about 20%. Overall, about 57% of the existing culverts in the city are undersized for full development design flows. Generally, flood design frequencies are 25-year return periods for most of the larger open channels and 10-year return periods for the piped areas. For the 1996 flood in Sweet Home, responses to the 1996 Flood Damage Survey (City of Sweet Home All Hazard Mitigation Committee) indicated that only 36% of respondents identified the source of flood water as being a creek or river with the associated (mapped) floodplain. Furthermore, 27% of the survey respondents reported flooding from groundwater and runoff. An additional 16% of the respondents reported storm water ditches and culverts as the sources of flood waters causing problems. Many respondents reported flood waters from more than one of the above sources. These historical data clearly indicate that portions of the existing storm water drainage system are inadequate during major storm events. The Sweet Home Master Storm Drainage Plan has detailed information on numerous locations within the city where improvements to the storm water drainage system are desired. However, a comprehensive inventory of locations where storm water flooding is particularly problematic (e.g., resulting flooding significantly affects, roads, buildings, or other facilities) is still not available. However, the locations outside of the mapped flood plains which experienced significant flooding during the 1996 flood and the 1998 Thanksgiving flood are certainly among the sites subject to significant storm water drainage flooding. A partial list of these sites, extracted from Map 6-1 above and narratives of Sweet Home s flood experience in 1996 and 1998, is given below: 1. portions of Sweet Home (around 12 th Avenue, including the City Hall area), which appear to be subject to storm water drainage flooding as well as to overbank flooding from Ames Creek. 2. area along Long Street from 35 th to 45 th Avenues, especially east of 43 rd Avenue. 3. along Mountainview Road between Ames Creek Drive and Elm St. 4. area around 1 st Avenue and Westwood Lane 5. area west of 9 th Avenue 6. area east and west of 18 th Avenue north of Tamarack St. 7. area east of 12 th Avenue, around Quince St. and Poplar St. 8. area east of Clark Mill Rd. 9. area along 47 th Avenue north of Main St. 10. area along Green River Road. 6.5 Inventory Exposed to Flood Hazards in Sweet Home According to the 1996 Flood Damage Survey (City of Sweet Home All Hazard Mitigation Committee), 232 properties in Sweet Home lie within the 100-year flood plain boundaries. These properties include mostly residential properties, but also include commercial properties in the downtown area, and a number of public buildings, including City Hall and the water treatment and wastewater treatment plants. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-10

75 To quantify the level of flood hazard for these properties, it is necessary to determine the elevations of these structures. Only by determining the first floor elevation of each of these potentially flood-prone structures, can the level of flood hazard (frequency and severity of flooding) be calculated accurately. Acquiring such elevation data is recommended as a high priority. Similarly, acquiring elevation data for additional structures within the 500-year flood plain as well as for structures in other flood-prone areas outside of mapped floodplains would greatly increase the accurate of hazard, inventory, and vulnerability assessments. The best structure elevations (first floor elevations) are those determined accurately by surveying. Flood insurance certificates generally include survey elevation data. Absent survey data, however, useful estimates of elevations for structures can often be made by reference to elevations of nearby structures or public infrastructure with surveyed elevation data. In addition to elevation data, quantifying the level of risk faced by these structures requires basic data about each structure, including building data (square footage, number of stories, with or without basement), and information on the type and importance of function (residential, commercial, public). Further details are given in the Appendix Examples of Mitigation Projects and Benefit-Cost Analyses. As noted above, some areas of Sweet Home, outside of the mapped floodplains, are also subject to relatively high levels of flood risk. To quantify the level of flood risk posed by these areas, historical data should be compiled to include the frequency and severity of flooding. Severity of flooding can include estimates of past damages, if available, and/or simple narratives reporting whether the flooding in a given area is limited to street flooding only, or affects yards or buildings as well. 6.6 Flood Insurance Data for Sweet Home The NFIP maintains nationwide databases of flood insurance policies and repetitive loss properties. The NFIP database for Sweet Home lists 30 flood insurance properties for the Sweet Home, CID # There are no known claims that have been filed since the last update of this plan in No properties in Sweet Home are on the NFIP list of repetitive loss properties. Overall, these NFIP data showing only a few flood insurance policies and no properties on the repetitive loss list reflect the fact that relatively few structures in Sweet Home are at high flood risk. The City adopted an implementing ordinance in 1989 for construction within the 100 flood plain, codified as Sweet Home Municipal Code Chapter This Chapter was update after Community Assistance visit from staff of the Oregon DLCD in 2005; this Chapter of the Code continues in 2015 to serve the City in its implementation efforts to meet the NFIP requirements. Additionally, the City provides the planning staff with training opportunities in flood plain management and reviews each Building Permit, identifying properties FIRM classification, attaching maps and aerial photos to Permits, and identifying the need for Certification of Elevation information for Permits. The Plan Review for each property identified as having the 100 year flood plain will then be required to meet the standards of the City of Sweet Home and the applicable building codes. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-11

76 6.7 Estimating Flood Losses and Flood Risk For most residential structures and many similar commercial and public structures, the likely amount of building damage from floods of any given depth can be estimated approximately using FEMA depth-damage tables. These depth damage tables are derived from Federal Insurance Administration flood insurance claims data for several million properties and thus represent typical damage levels for typical structures. Although actual damages will vary somewhat from structure to structure, depending also on flood conditions such as duration, velocity, and degree of contamination, these typical values represent a good starting point to estimate flood damages for typical structures and thus to help quantify the level of flood risk. Current FEMA depth-damage data for typical structures are given in the Appendix Example Mitigation Projects. In estimating flood losses or evaluating flood risk (for a structure or a whole community) it is very important to recognize that the economic impact of floods includes not only damages to buildings and contents but other economic impacts as well, including: 1. damages to yards, vehicles, and outbuildings (not in depth damage data above), 2. displacement costs for temporary quarters while repairs are made, 3. loss of business income, and 4. loss of public services. In some cases, these economic impacts of floods can be a significant fraction of building and contents damages, or even larger, especially for critical facilities or critical infrastructure. FEMA s publication What is a Benefit? Guidance for Benefit-Cost Analysis provides an excellent primer, along with typical values and simple economic methods, to place monetary values on the loss of function of buildings, critical facilities, roads and bridges, and utility systems. 6.8 Flood Mitigation Projects Potential mitigation projects to reduce the potential for future flood losses cover a wide range of possibilities. For either the South Santiam River or the creeks, it would be theoretically possible to reduce future flood losses by building levees or flood walls. In practice, however, such projects are often very expensive and have a host of environmental and other regulatory hurdles. Given that much of the potential flooding within mapped floodplains in Sweet Home is from Ames Creek, more realistic mitigation projects might include further channel improvements for Ames Creek to lower flood levels by increasing the conveyance capacity of the channel. Another possibility for Ames Creek would be to construct detention ponds upstream (outside of Sweet Home) to temporarily store water during high rainfall periods. Detention ponds are basically leaky dams, designed to be dry during normal conditions. Detention ponds typically have restricted outlets with controlled flow rates. Thus, during periods of high inflow into the pond, water is stored temporarily and then gradually released. The effect of detention ponds is to lower peak discharge values and thus to lower peak flood elevations. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-12

77 For areas of Sweet Home subject to flooding from storm water drainage, various storm water drainage system improvements may be desirable. Typical improvements include upgrades to the size of drainage ditches or storm water drainage pipes and upgrades to pumping capacity (for pumped portions of drainage systems) or construction of local detention ponds. For critical facilities at low elevations with high flood risk, such as the water and wastewater treatment plants, construction of berms or floodwalls to protect the facilities may be desirable. For residential, commercial or public facilities at high flood risk, elevation of structures or, for structures at very high flood risk, acquisition and demolition are potential mitigation options. Elevation and acquisition (especially), are expensive mitigation options that are generally not cost-effective unless the levels of flood hazard and flood risk are rather high. That is, these mitigation options are most attractive for structures deep in the flood plain (i.e., with first floors below the 10-, or 20-, or 30-year flood elevations). For structures outside of mapped floodplains, elevation or acquisition would likely be cost-effective only for structures with a strong history of major, repetitive flood losses. For structures near the fringe of the 100-year flood plain, near the 100-year flood level, or with some history of repetitive flood losses, various small scale flood loss reduction measures such as elevation of furnaces and utilities may be desirable. Table 6-2 includes flood mitigation action items from the master Action Items in Chapter 4. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-13

78 OG OG OG OG 1-2 Yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 6-2: Flood Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Flood Mitigation Action Items Flood Mitigation Action Items: Within Floodplains ST #1 Begin process of code revisions for storage in floodplains. CCDD City X X LT #1 Survey elevation data for structures within the 100-yr floodplain, including coordination with Linn County Planning on use of LIDAR imaging for elevation information. CCDD City X LT #2 For structures within the 100-year floodplain and especially for structures deep in the floodplain, explore mitigation options with property owners. CCDD City X X X Flood Mitigation Action Items: Outside Floodplains ST #1 Complete the inventory and mapping of locations in Sweet Home subject to frequent storm water flooding. CCDD City X LT #1 For locations with repetitive flooding and significant damages or road closures, determine and implement remedies. CPWD City X X X Same as Table 4-3 in Chapter 4, page 4-7 G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 6-14

79 7.1 Overview 7.0 SEVERE 1 STORMS Severe storms affecting Sweet Home are usually characterized by a combination of heavy rains and high winds. Heavy rains can result in flooding, as well as debris slides and landslides. High winds commonly result in tree falls which primarily affect the electric power system, but which may also affect buildings and vehicles. This Chapter deals primarily with the rain and wind effects of severe storms. Larger scale flooding is addressed in Chapter 6. Debris flows and landslides are addressed in Chapter 8. Severe storms can also involve ice and snow, most commonly at higher elevations than Sweet Home, but the City has experienced heavy ice and snow events. The most likely impact of snow and ice events on Sweet Home are road closures limiting access/egress to/from Sweet Home, especially roads to higher elevations such as Highway 20 east of Sweet Home. Severe storms with heavy wet snow and ice storms also may result in power outages from downed transmission lines and/or poles. Average annual snowfall in Sweet Home (Foster Dam weather station) is only 1.4. Since the Foster Dam weather station was established in 1968, maximum monthly snowfall has been 12 (January 1971), with maximum seasonal snowfall of 15.3 ( ). Over 35 years of records, annual snowfalls were 2 or more only 7 times, most recently in However, major snow storm events do occur occasionally. Major snow storms affecting the Willamette Valley occurred in 1884, 1892, 1909, 1916, 1919, 1937, 1950, 1969, and January 1950 snowfalls were especially high, with 54 in Albany and 36 in Eugene. In January 1969, Eugene had 47 of snow. Thus for Sweet Home, most winters result in little snowfall, with major storms of 10 or more snow occurring typically about every 10 or 20 years. There are few practical mitigation actions for such infrequent major snow storms, other than common sense measures applicable to many hazards, such as encouraging residents to maintain emergency supplies of food and water for a few days and emergency generators for critical facilities. For completeness, we also briefly address other severe weather events, including hail and lightning strikes and tornadoes. Hail events are possible in Sweet Home, generally during summer thunderstorms, with the most recent significant event being August 4, However, hail damage is generally minor and few practical mitigation alternatives are applicable to hail. Similarly, lightning strikes are possible in Sweet Home. However, lightning strike damage is generally relatively minor and few practical mitigation alternatives are applicable to lightning, other than installing lightning arrestors on critical facilities subject to lightning damage. Tornadoes also do occur occasionally in Oregon. However, Oregon is not among the 39 states with any reported tornado deaths since Historically, tornadoes in Grant County were reported to have killed a total of four people in 1894 and Very minor tornadoes have been reported in Linn County, including two in Albany in 1990 and In 2012, an EF 2 tornado did considerable damage in Aumsville, Marion County, to the north of Sweet Home. Climate and weather conditions in Oregon make the occurrence of major tornadoes extremely unlikely. Thus, for Sweet Home, the risk posed by tornadoes is negligible. Furthermore, the only practical mitigation actions for tornadoes are public warnings and taking shelter. 1 Previously this chapter had been entitled Winter Storms, but has been renamed in recognition of the fact that although severe storms are more likely to occur in the winter months, they can occur during any season of the year. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-1

80 7.2 Severe Storms Hazard Assessment Rain Hazard Data Severe storms usually include heavy rainfall. The potential impact of heavy rainfall depends on both the total inches of rain and the intensity of rainfall (inches per hour or inches per day). In the context of potential flooding, rainfall also includes the rainfall equivalent from snow melt. Large drainage basins, such as that for the Willamette River have response times of several days or more: the total rainfall (plus snow melt) over periods of several days or more is what determines the peak level of flooding along the Willamette. Smaller rivers, such as the South Santiam River would have response times of a day or two. However, for the South Santiam River, flood levels are predominantly controlled by the Green Peter and Foster Dams, and thus the usual natural correlation between rainfall events and flood levels does not apply. Smaller drainage basins, such as Ames Creek, have much shorter response times so levels of flooding may be governed by rainfall totals over a period of an hour to a few hours for very small drainage basins to periods of a day or so for somewhat larger drainage basins. Rainfall data maps for Linn, Benton, and Lincoln Counties were presented as Figures 4.1 to 4.4, in the Phase One Regional All Hazard Mitigation Master Plan for Benton, Lane, Lincoln, and Linn Counties (Phase One Plan, 1998). These state-of-the-art rainfall maps were prepared by George Taylor, the Oregon State Climatologist at that time, using what is known as orographic modeling. Rainfall gauge stations are relatively widely spaced. However, for modeling the localized impacts of heavy rainfall, higher resolution rainfall maps are needed. Orographic modeling considers topography, wind effects, and soil conditions and calibrates rainfall contours to conform to measured runoffs from stream gauge readings. Using these modeling techniques, rainfall maps are produced with higher spatial resolution than would be possible relying solely on rain gauge data. These rainfall maps include contour maps for annual precipitation, and 24-hour precipitation totals for storms of three severities (recurrence intervals): 2-year, 25-year, and 100-year. For Sweet Home, these rainfall data are summarized in Table 7-1. Table 7-1: Sweet Home and Linn County Rainfall Data Rainfall Amount (inches) Period Sweet Home Eastern Linn County (maximum) Average Annual year 24 hour year 24 hour year 24 hour For reference, rainfall data are also shown for the highest precipitation area in eastern Linn County, which is the western slope of the Cascades near the crest. The statistical rainfall amounts for the Cascades are nearly double those for Sweet Home. To put these data in perspective, it is noted that statistical rainfall amounts for the Coast Range (e.g., Lincoln County) are nearly double those in the Cascades. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-2

81 For Sweet Home, the annual, and 2-year, 25-year, and 100-year rainfall totals are moderately high, but substantially lower than those experienced in the Cascades or in the Coast Range. Thus, Sweet Home has a moderately high potential for localized flooding from severe storm rainfall events. The frequency of rainfall events is interpreted in the same manner as the frequency of flood events. Thus, a 2-year rainfall event simply means that such rainfalls have a 50% chance of happening in any given year. A 25-year or 100-year rainfall event mean simply that such rainfalls have a 4% or 1% chance, respectively, of happening in any given year. For modeling the flood impacts of severe storms we use the 24-hour precipitation maps. The 24-hour precipitation totals are a reasonable measure of flood risk for small drainage basins. Longer duration precipitation totals (several days or a week) govern flooding on larger rivers, but such flooding is already included in the modeling behind FEMA s floodplain mapping and covered by the discussion of flood hazards in Chapter 6. For Sweet Home, it is noted that 2-year and 25-year 24-hour precipitation totals are 3" or more and 4.5, respectively. Such totals are high enough to generate significant potential localized flooding problems. However, whether or not localized flooding does occur depends on specific local drainage conditions. For example, 4.5" of rain in one area may cause no damage at all, while 4.5" of rain in a nearby area may cause road washouts and flooding of buildings. Thus, while the rainfall data shown in Table 7-1 give a Sweet Home and regional overview of the potential for severe storm flooding, but whether or not flooding occurs at specific sites depends heavily on specific local drainage conditions. For Sweet Home, identification of specific sites subject to localized flooding during severe storms is based on historical occurrences of repetitive flooding events. Such sites in Sweet Home, where localized storm water drainage flood has been repetitive and problematic, were summarized in Section 6.3 and shown on Map 5 in Chapter Wind Hazard Data Wind speeds associated with severe storms vary depending on meteorological conditions, but also vary spatially depending on local topography. For Linn County, the general wind hazard levels are fairly uniform across the county. In the hilly areas, however, the level of wind hazard is strongly determined by local specific conditions of topography and vegetation cover. The best overall measure of the level of wind hazard for Sweet Home is provided by the design wind speeds in the 2012 International Building Code (IBC) for Sweet Home s location. These design wind speeds are based on the American Society of Civil Engineers publication: Minimum Design Loads for Buildings and Other Structures (2010), which is commonly referred to as ASCE These publications have design wind speeds for four categories of building occupancy and use: Category I (buildings that represent a low risk to human life), Category II ( ordinary buildings not in the other three categories), Category III (buildings whose failure could pose a substantial risk to human life), and Category IV (buildings containing hazardous materials). City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-3

82 The design wind speeds are as follows: Category I: 105 mph (45 meters/second) return period of about 300 years (15% chance in 50 years), Category II: 110 mph (49 meters/second) return period of about 700 years (7% chance in 50 years), and Category III and IV: 115 mph (52 meters/second) return period of about 1,700 years (3% chance in 50 years).a more detailed regional overview of wind hazards is shown by the data in Figures 7.2 and 7.3 which show contours of wind speed (in kilometers per hour) for western Oregon (Wantz and Sinclair, Distribution of Extreme Wind Speeds in The Bonneville Power Administration Service Area, Journal of Applied Meteorology, Volume 20, , 1981). These data are for the standard meteorological data height of 10 meters (about 39 feet) above ground level. Figures 7-2 and 7-3 show wind speed contours for recurrence intervals of 2-years and 50-years, respectively. These data are for sustained wind speeds. Peak gusts are commonly 30% or so higher than the sustained wind speeds. These windspeed data are more than 30 years old but are still representative of wind hazard levels s in Oregon overall and in Sweet Home in particular. More recent data with this level of spatial resolution were not available when the 2015 update of the mitigation plan was completed. For Sweet Home, the 2-year and 50-year sustained wind speeds are about 60 km/hour and 100 km/hr, respectively. These values correspond to 2- and 50-year wind speeds of about 37 miles/hr and 62 miles/hr, respectively. These 2-year wind speeds are too low to cause widespread substantial wind damage. However, there may be significant local wind damage at sites where local wind speeds are higher or where there are especially exposed locations, such at the boundary between clear cut and forested areas. However, these 50-year recurrence interval wind speeds are high enough to cause widespread wind damage. Damage may be severe at particularly exposed sites. Thus, for Sweet Home, severe storms with significant direct wind damage are not likely every year or every few years, but perhaps once every decade or so, on average, with major wind storm events happening at intervals averaging a few decades. For reference, it is noted that maximum winds (fastest mile wind speeds) observed in nearby Eugene range from 29 to 37 mph during June, July and August and from 40 to 63 mph for the other months, with fall/winter months having the highest recorded wind speeds. The maximum recorded wind speed in Eugene is 63 mph during the October 12, 1962 windstorm event. Because of topographic effects, typical wind speeds in Sweet Home might be expected to be somewhat higher than those in Eugene. However, a private meteorological firm collecting data for Cascade Timber Consulting noted that typical wind speeds in Sweet Home are often lower than in Eugene, which is more exposed than Sweet Home. The hills south of Sweet Home partially block southerly winds. In any case, the Eugene data give a general picture of the wind hazard level for Sweet Home. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-4

83 Figure 7-2: Wind Speed Contours for 2-Year Recurrence Interval (km/hour) City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-5

84 Figure 7-3: Wind Speed Contours for 50-Year Recurrence Interval (km/hr) Historical Severe Storm Data for Sweet Home Severe storms can affect Sweet Home directly, with damage within the City, or indirectly, with damage outside Sweet Home but affecting transportation to/from Sweet Home and/or utility services (especially electric power). Historically, Sweet Home has often been subject to both direct and indirect impacts of severe storms. The severe storms that affect Sweet Home are generally not local events affecting only Sweet Home. Rather, the severe storms are typically large cyclonic low pressure systems moving from the Pacific Ocean and that thus usually affect large areas of Oregon and/or the whole Pacific Northwest. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-6

85 Historical severe storm data compiled by the Portland Office of the National Weather Service ( list the following major severe storm events with substantial wind damage in Oregon: December 1-3, 2007 December 15, 2005 February 7, 2002 December 12, 1995 November 13-15, 1981 March 25-26, 1971 October 2, 1967 March 27, 1963 October 12, 1962 November 3, 1958 December 21-23, 1955 December 4, 1951 November 10-11, 1951 April 21-22, 1931 January 20, 1921 January 9, The website referenced above has informative narrative summaries of each severe storm event, including wind speed data and damage reports. Similar compilations of historical wind storm data have been compiled by Wolf Read, The Storm King, at ( The OSU website also has a vast archive of historical severe storm data for Oregon. The impacts of the major historical winter storm events listed above varied significantly with geographic location. Similar variations in impacts occur as well with the numerous smaller severe storm events. However, in terms of sustained wind speeds in the Willamette Valley and damage levels, the 1880 and 1962 storms stand out as the most severe such events. The major severe storm event to impact Sweet Home is the February 7, 2002 storm. National Weather Service data show peak sustained winds and peak gusts at the Eugene Airport of 49 mph and 70 mph, respectively. Wind speeds in Sweet Home were probably comparable to these Eugene data. The 2002 windstorm event had significant impacts on Sweet Home, primarily from tree falls. Widespread tree falls in Sweet Home resulted in significant damages to utility lines and poles as well as damages to vehicles and buildings. The entire City of Sweet Home experienced an electric power outage of about 24 hours, with outlying areas experiencing outages of nearly five days duration. The local damage within Sweet Home would have resulted in some power outages for portions of the City. However, the city-wide outage resulted from downed lines and poles in the transmission lines feeding substations in Sweet Home and thus would have occurred whether or not there were local damages to utility lines within Sweet Home Severe Storm Events Since the 2009 Update of the SHMP The major storm event of this five year period occurred in February On April 4, 2014, President Obama issued a major disaster declaration for the State of Oregon including Linn County and therefore Sweet Home -- triggering the release of Federal funds to help communities recover from a Severe Winter Storm that occurred February 6-10, Details of the disaster declaration and assistance programs included: Declaration Number: FEMA-4169-DR Public Assistance (PA): Assistance for emergency work and the repair or replacement of disaster damaged facilities: PA-Designated Counties: Benton, Lane, Lincoln, and Linn Counties. Hazard Mitigation (HM): Assistance for actions taken to prevent or reduce long-term risk to life and property from natural hazards: City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-7

86 HM-Designated Counties: All counties in the State of Oregon are eligible to apply for assistance under the Hazard Mitigation Grant Program Potential Changes in Global Climate: Implications for Local Mitigation Planning As a follow up to Section 7.2.4, it is worth noting that Sweet Home experienced in December 2013 and again more severely in February 2014 considerable snow fall and prolonged below freezing temperatures, with accompanying power outages and school closures. Also, most of continental United States, many parts of Europe and India experienced severe weather during the winter of Scientists around the world (at the time of this 2015 update) are discussing whether or not these are signs of global climate change. These discussions include rapidly rising atmospheric CO 2 levels, shrinking polar ice caps resulting in less sunlight reflected from the polar regions, rising global average temperatures, and potential changes of the usual patterns of the jet stream in the northern hemisphere. City staff and the Sweet Home Mitigation Planning Committee should pay attention to these discussions in the coming months and years for potential implications to mitigation planning for the City. 7.3 Severe Storm Risk Assessment Severe storm flooding and wind impacts may affect both infrastructure and buildings. Localized flooding from severe storms very commonly affects the transportation system, especially roads. Severe storms will result in numerous road closures due either to washouts or due to depth of water on road surfaces. Such localized flooding also affects buildings located in the flooded areas. Additional road closures are likely in some events from landslides/mudslides as well as from snow/ice storms. Wind impacts from severe storms arise primarily from tree falls, which may affect vehicles and buildings, to some extent, but whose primary impact is often on utility lines, especially electric power lines. Widespread wind damages may result in widespread downing of trees or tree limbs with resulting widespread downage of utility lines. Such tree-fall induced power outages affect primarily the local electric distribution system, because transmission system cables are generally less prone to tree fall damage because of design and better treepruning maintenance. In severe wind storms, direct wind damage or wind driven debris impacts on buildings cause building damages, especially for more vulnerable types of construction such as some types of manufactured homes. As discussed above in Section 7.1, both severe storm flood hazards and severe storm wind hazards have highly localized impacts. The location and severity of such impacts depend very strongly on specific local conditions. Therefore, it is difficult to make regional risk assessment or loss estimates from mapping the hazards and overlaying the inventory: such a risk assessment simply requires too much detailed data which are not available. An alternative approach is to document the severity and locations of severe storm flood and wind damage from historical events. A good example of this approach is the excellent summary of damages and losses experienced in the report documented the damages in the February 1996 floods: The Cascades West Region of Oregon and the February Flood of 1996: A Regional Flood Recovery Plan for Benton, Lane, Lincoln, and Linn Counties, Oregon Cascades West Council of Governments, November City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-8

87 For more quantitative risk assessment of localized flooding and wind damages arising from severe storms, the best approach is to systematically gather data on sites of repetitive damages due to localized flooding or wind damages. By documenting (and mapping using GIS) the sites of repetitive damage events, along with documentation of the type and cost of damages and losses, the most seriously impacted sites can be clearly identified. Clearly, such repetitive loss sites with significant damages are prime candidates for mitigation actions. The potential impacts of severe storms on Sweet Home are summarized in Table 7-4. Table 7-4: Potential Impacts of Severe Storms on Sweet Home Inventory Portion of Sweet Home affected Buildings Streets within Sweet Home Roads to/from Sweet Home Electric power Other Utilities Casualties 7.4 Mitigation of Severe Storm Impacts Probable Impacts Entire city may be affected by road closures or loss of electric power; otherwise direct damages to buildings and infrastructure are likely to be localized and relatively minor Isolated minor damage from tree falls, some buildings affected by flood damage in major storms, especially in the storm water drainage problem areas identified in Section 6.3 Minor road closures due to tree falls and flooding; limited impact because of short detour routes within Sweet Home Potential closures of major highways due to snow, debris flows or landslides, localized flooding and tree falls Loss of electric power may be localized due to tree falls on local distribution lines or affect entire city if tree falls affect transmission lines feeding Sweet Home Generally minor or no impacts on other utilities from winter storms Small potential for casualties (deaths and injuries) from tree falls or contact with downed power lines Potential mitigation projects for severe storms address any of the aspects of such storms, including floods (see Chapter 6), winds, and landslides (see Chapter 8). See also Chapter 13 for additional discussion of the disruptions to utility and transportation systems. For severe storm flooding, the mitigation measures discussed in Chapter 6 for local storm water drainage flooding are exactly the mitigation measures for the flood aspects of severe storms. Common mitigation projects include: upgrading storm water drainage systems, construction of detention basins, and structure-specific mitigation measures (acquisition, elevation, flood proofing) for flood-prone buildings. For roads subject to frequent severe storm flooding, possible mitigation actions include elevation of the road surface and improved local drainage. For utilities subject to frequent severe storm flooding, possible mitigation actions include improved local drainage, elevation or relocation of the vulnerable utility elements to non-flood prone areas nearby. For wind effects of severe storms, the most common and most effective mitigation action is to increase tree pruning effects, because a high percentage of wind damage to utilities, buildings, vehicles, and people arises from tree falls. Pruning of trees subject to falling on utilities, buildings, vehicles, and people is an effective mitigation measure. However, economic, political and aesthetic realities place limits on tree pruning as a mitigation action. Future wind storm damage in Sweet Home could be almost eliminated by cutting down all large trees in the City. Obviously, such an extreme mitigation measure is neither practical nor desirable for many reasons. Effective tree pruning mitigation programs focus on limited areas where tree falls have a high potential to result in major damages and economic losses. High priority areas include examples such as the following: City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-9

88 1) Transmission lines providing electric power to Sweet Home, 2) Major trunk lines providing the backbone of the electric power distribution system within Sweet Home, 3) Distribution lines for electric power to critical facilities in Sweet Home, 4) Specific circumstances where falling of large trees poses an obvious threat to damage buildings and/or people or close major transportation arteries. Detailed analysis, benefit-cost analysis, and prioritization of severe storm mitigation projects for localized flooding or wind effects follows a methodology essentially identical to that described in Section 3.2 of the Phase One Regional All Hazard Mitigation Master Plan for Benton, Lane, Lincoln, and Linn Counties (1998). The analysis for flooding outside of mapped floodplains uses a frequency-damage relationship to annualize risk and then to estimate the benefits of alternative mitigation projects. This same approach is applicable to evaluation of mitigation projects for wind effects of severe storms as well as for flood effects. The Table 7-5 includes severe storm mitigation action items from the master Action Items in Chapter 4. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-10

89 OG OG OG OG OG 1-2 Yrs 1-2 Yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built -Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; LCSC = Linn County Shelter Committee xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Severe Storm Mitigation Action Items Table 7-5: Severe Storm Mitigation Action Items Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 ST #1 Assess need for back-up power generators for emergency shelters in SH. SHMPC City 7 X ST #2 Identify critical need locations, vulnerable populations, and vulnerable independent individuals. CCDD City X X X LT #1 Consider upgrading lines & poles to improve wind/ice loading, undergrounding critical lines, and adding interconnect switches to allow alternative feed paths and disconnect switches to minimize outage areas. Electrical Utility (PPL) PPL X X X LT #2 Encourage Pacific Power (PPL) to prioritize a coordinated emergency response (including enhanced communications) with City Public Works. CPWD; PPL PPL X X X LT #3 Assess needs for back-up power generators for all City-owned designated critical facilities and ensure that the highest priority critical facilities have generators or are wired to accept plug-in generators, as has been done for the waste water treatment plant (generator) and the new water treatment plant (wiring set up). Include assessing generator needs for City Hall and the Community Center. CPWD City X X X LT #4 Enhance tree pruning efforts especially for transmission lines and trunk distribution lines. PPL; CTC City, PPL X X X LT #5 Continue City-wide efforts encouraging property owners to keep trees trimmed near their electrical service drops. SHMPC; CTC City X X X X Same as Table 4-4 in Chapter 4, page 4-8. G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 7-11

90 8.1 Landslide Overview and Definitions 8.0 LANDSLIDES The term landslide refers to a variety of slope instabilities that result in the downward and outward movement of slope-forming materials, including rocks, soils and artificial fill. Four types of landslides are distinguished based on the types of materials involved and on the mode of movement. These four types of landslides are illustrated in Figures 8.1 to 8.4 from the Regional All Hazard Mitigation Master Plan for Benton, Lane, Lincoln, and Linn Counties (Phase One, Technical Appendix, 1998) which includes a more technical discussion of these four types of landslides. 1) Rockfalls are abrupt movements of masses of geologic materials (rocks and soils) that become detached from steep slopes or cliffs. Movement occurs by free-fall, bouncing and rolling. Falls are strongly influenced by gravity, weathering, undercutting or erosion. 2) Rotational Slides are those in which the rupture surface is curved concavely upwards and the slide movement is rotational about an axis parallel to the slope. Rotational slides usually have a steep scarp at the upslope end and a bulging toe of the slid material at the bottom of the slide. Roads constructed by cut and fill along the side of a slope are prone to slumping on the fill side of the road. Rotational slides may creep slowly or move large distances suddenly. 3) Translational Slides are those in which the moving material slides along a more or less flat surface. Translational slides occur on surfaces of weaknesses, such as faults and bedding planes or at the contact between firm rock and overlying loose soils. Translational slides may creep slowly or move large distances rather suddenly. 4) Debris Flows (mudflows) are movements in which loose soils, rocks and organic matter combine with entrained water to form slurries that flow rapidly downslope. All of these types of landslides may cause road blockages by dumping debris on road surfaces or road damages if the road surface itself slides downhill. Utility lines and pipes are prone to breakage in slide areas. Buildings impacted by slides may suffer minor damage from small settlements or be complexly destroyed by large ground displacements or by burial in slide debris. Also, as evidenced by 1997 severe storms in Oregon, landslides may also result in casualties. There are three main factors that determine susceptibility (potential) for landslides: 1) slope, 2) soil/rock characteristics, and 3) water content. Steeper slopes are more prone to all types of landslides. Loose, weak rock or soil is more prone to landslides than is more competent rock or dense, firm soils. Finally, water saturated soils or rock with a high water table are much more prone to landslides because the water pore pressure decreases the shear strength of the soil and thus increases the probability of sliding. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 8-1

91 Figures 8-1 to 8-4: Major Types of Landslides As noted above, the water content of soils/rock is a major factor in determining the likelihood of sliding for any given slide-prone location. Thus, most landslides happen during rainy months, when soils are saturated with water. However, landslides may happen at any time of the year. In addition to landslides triggered by a combination of slope stability and water content, landslides may also be triggered by earthquakes. Areas prone to seismically triggered landslides are exactly the same as those prone to ordinary (i.e., non-seismic) landslides. As with ordinary landslides, seismically triggered landslides are more likely for earthquakes that occur when soils are saturated with water. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 8-2

92 8.2 Landslide Hazard Assessment for Sweet Home Areas with high landslide potential within Sweet Home s urban growth boundary are shown on Map 6-2 (Chapter 6) and Map 8-1 (below). The high landslide potential areas on Map 1 represent primarily surficial debris flow hazard areas. The high landslide potential areas on Map 3 represent earthquake induced landslides which are also representative of rockfalls, rotational slides, and translational slides from non-earthquake events (such as heavy rainfalls). Fortunately, only limited areas within Sweet Home s urban growth boundary are shown as high landslide potential areas and most of these areas have little or no development, at present. In general, landslide hazard areas are areas with steep slopes of potentially unstable soils or rock. Moderate landslide potential areas thus include most of the hilly areas within Sweet Home s urban growth boundary. High landslide potential areas include: 1) an area just outside the urban growth boundary on the north side of the South Santiam River, 2) two small areas just outside the northwest corner of Sweet Home s urban growth boundary, across the South Santiam River, and 3) several areas in the hilly area in the southern portion of Sweet Home. Of these three areas, only the third area has significant development at present. The high landslide potential area includes the footprints of about a dozen homes, according to the DOGAMI map, although development is continuing in this general area. These at-risk homes are located along 42 nd and 43 rd Avenues, south of Coulter Lane, just outside the city limits. More detailed landslide hazard assessment requires a site-specific analysis of the slope, soil/rock and groundwater characteristics at a specific site. Such assessments are often conducted prior to major development projects in areas with moderate to high landslide potential, to evaluate the specific hazard at the development site. Apparently, there are no historical records of significant landslide/mudslide/debris flow events within Sweet Home, although such events are very common in the hilly and mountainous parts of Oregon. DOGAMI conducted a statewide survey of landslides arising from the severe winter storms in February 1996, November 1996, December 1996 and January 1997 and found 9,582 documented landslide locations. The actual number of landslides was estimated to be many times the documented number. 8.3 Landslide Events Since 2009 Since the 2009 there have been no significant landslides in Sweet Home. 8.4 Landslide Risk Assessment for Sweet Home In this section, we review a methodology for estimating landslide losses due to severe storm induced landslides. Severe storms with intense rainfalls are the most common trigger for landslides in Oregon, including Linn County and Sweet Home. Major storms with intense rainfall can result in numerous landslides in slide-prone areas. Of course, at any given slide-prone location, landslides can occur with or without severe storms, but such occurrences are isolated and not likely to result in the type of fairly widespread landslide impacts that are possible during severe storms. Widespread landslides City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 8-3

93 can also be triggered by earthquakes, especially if the earthquake occurs during the rainy season when soils are saturated. See Chapter 10 (Earthquakes) for further commentary on earthquake-triggered landslides. As with any risk assessment, we must overlay the hazard assessment (frequency and severity of landslides) with the inventory exposed to the hazard (value and vulnerability). The Level One risk assessment method given in the Regional All Hazard Mitigation Master Plan for Benton, Lane, Lincoln, and Linn Counties (Phase One, 1998) considers: 1) the extent of landslide susceptible areas, 2) the inventory of buildings and infrastructure in landslide susceptible areas, 3) the severity of storm event (inches of rainfall in 24 hours), 4) the percentage of landslide susceptible areas that will move and the range of movements (displacements) likely, and 5) the vulnerability (amount of damage for various ranges of movement). For Sweet Home, the threat posed by landslides is limited by the relatively small inventory of buildings (about a dozen homes) and roads in landslide prone areas. Thus, the maximum amount of damage is limited by the value of these homes. Nevertheless, a significant landslide in the south hills area could damage or destroy one or more homes, as well as damaging utilities and roads in the area, as well as posing some level of life safety risk for residents. In addition to direct landslide damages within Sweet Home, the City is also subject to the economic impacts of road closures (e.g., Highway 20) due to landslides. The February 1996 severe storms provided numerous examples of landslide damages, especially to the road system, with landslides and mudslides closing many roads in Linn County and other nearby counties. The potential impacts of landslides on Sweet Home are summarized in Table 8-1 below. Table 8-1: Potential Impacts of Landslides on Sweet Home Inventory Portion of Sweet Home affected Buildings Streets within Sweet Home Roads to/from Sweet Home Electric power Other Utilities Casualties Probable Impacts Landslides are likely to directly affect only limited portions of Sweet Home as shown above on Map 3. Medium and high landslide potential areas are residential. Small landslides are likely to affect no buildings or only 1 or 2 buildings. Larger landslides could affect several buildings. Minor road closures possible from landslides; limited impact because of short detour routes within Sweet Home Potential closures of major highways due to landsides, especially roads into the Cascades. Potential for localized loss of electric power due to landslides affecting power lines in or near Sweet Home Potential minor outages of water, wastewater and natural gas from pipe breaks from landslides. Probable impacts are very localized. Landslides that impact buildings or roads could result in a small number of casualties (deaths and injuries) City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 8-4

94 Map 8-1: DOGAMI Earthquake Induced Landslide Hazard Map for Sweet Home City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 8-5

95 8.5 Mitigation of Landslide Risk Mitigation of landslide risks is often quite expensive. In some cases, slope stability can be improved by addition of drainage to reduce water pressure, by construction of appropriate retaining walls or by other types of geotechnical remediation. In some cases, buildings can be hardened to reduce damages. An alternative mitigation strategy for already built buildings or infrastructure with high potential for landslide losses is to relocate the facilities outside of known slide areas. Mitigation of landslide risk can also be accomplished by effective land use planning to minimize development in slide-prone areas. Generally, such land use planning requires rather detailed geotechnical mapping of slide potential so that high hazard areas can be demarcated without unnecessarily including other areas of low slide potential. The impacts of slide damage on road systems can also be partially addressed by identifying areas of high slide potential or of repetitive past slide damages so that alternative routes for emergency response can be pre-determined. The Table 8-2 includes landslide mitigation action items from the master Action Items in Chapter 4. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 8-6

96 OG OG 1-2 yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built -Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 8-2: Landslide Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xx Landslide Mitigation Action Items Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 ST #1 Implementation of geo-tech work for new construction in previously identified areas subject to land slide. CPWD; CCDD City X X X X LT #1 Consider landslide mitigation actions for slides seriously threatening buildings or infrastructure. SHMPC; CPWD City X X X LT #2 Limit future development in high landslide potential areas. CCDD City X X X X X X Same as Table 4-5 in Chapter 4, page 4-9. G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 8-7

97 9.1 Overview 9.0 WILDLAND/URBAN INTERFACE FIRES Fire has posed a threat to mankind since the dawn of civilization. Fires may cause significant damage to property and may also result in deaths and injuries. For the purposes of mitigation planning, we consider three types of fires: structure fires, wildland fires, and wildland/urban interface fires. Structure fires are fires in urban, suburban or rural areas where structures (and contents) are the primary fire fuel. Wildland fires are fires where vegetation (grass, brush, trees) is the primary fire fuel. Wildland/urban interface fires are fires where the fire fuel includes both structures and vegetation. In 2011, according to National Fire Protection Association (NFPA) data there were 30,145 fire departments in the United States. Nearly 92% of these are all volunteer or mostly volunteer departments with only about 8% being career or mostly career fire fighting staff departments. However, the career fire departments tend to serve large communities. Thus, about 66% of the total population in the United States is served by career departments, while about 34% is served by volunteer departments. Because of the large number of fire departments and the absence of mandatory reporting requirements (either nationally or within most states), fire statistics data are incomplete. The best estimates for structure fires are annual estimates made by NFPA, based on surveys of fire departments. The best estimates for wildland fires are those compiled for federal forest lands by the United States Forest Service. The City of Sweet Home is bordered by a mix of agricultural land, grasslands, and forests. Map 9-1 shows the vegetation patterns for lands surrounding Sweet Home are shown in. Lands to the northeast, east, and south of Sweet Home are generally forested. Lands to the north and west of Sweet Home contain higher fractions of agricultural lands and grasslands, with some forested areas. The boundary of the City of Sweet Home appears to be approximately 60% forest lands. Given the large acreage of forest lands in immediate proximity to Sweet Home, the City as a whole, and especially the still developing areas on the southern edge of Sweet Home, may have significant risk from wildland/urban interface fires. 9.2 Fire Primer For this section of the SHMP, the focus is on wildland/urban interface fires. However, to provide a context for the discussion of wildland/urban interface fires, we first briefly review the characteristics of all three types of fires Structure Fires Structure fires are fires in urban, suburban or rural areas where structures (and contents) are the primary fire fuel. Ever since the first volunteer fire department was established in the United States in 1648, the primary focus of most fire departments has been to reduce the risk of structure fires. Historically, structure fires have posed the greatest threat to both property and life safety. In dealing with structure fires, fire departments have three primary objectives: first, minimize casualties; second, prevent a single structure fire from spreading to other structures; and third, minimize damage to the structure and contents. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-1

98 Map 9-1: Aerial Photograph Showing Vegetation Patterns in Sweet Home and Vicinity City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-2

99 In recent decades, the rate of structure fires (number of fires per year per 1,000 structures) and the total number of structure fires have declined sharply even though the number of structures has increased with increasing population. This decrease in structure fires is attributed to a number of factors, most importantly better building codes that have reduced both the numbers of ignitions and the likelihood that a small fire will quickly spread. Building code improvements include better wiring, smoke detectors, better design of furnaces, reduced use of portable heating devices, and the widespread use of fire resistant materials such as sheet rock and non-flammable roofs. In addition to the building code improvements, fire suppression capabilities have also improved over the decades. Improved water systems provide greater and more reliable water flows for fire suppression efforts. Better training, better communication equipment, better fire fighting equipment and apparatus have also all contributed to improved fire suppression capabilities. Widespread use of smoke detectors has also reduced the number casualties by providing occupants more warning time for evacuation. In recent decades, a decline in the percentage of smokers in the United States has also had a beneficial impact on the rate of accidental ignitions from careless handling of smoking materials. The decrease in the number of structure fires has been accompanied by a corresponding decrease in the numbers of deaths from structure fires as shown below in Table 9-1. Table 9-1: Recent History of Fire Deaths in the United States Year Fire Deaths , , , ,095 1 Fire deaths are as estimated by the National Fire Protection Association ( Despite the dramatic reductions over the decades, structure fires still cause a great deal of damage and many casualties. NFPA estimates for 2011 are that structure fires caused about 3,095 deaths and $9.7 billion in property damage. In addition to dealing with structure fires, urban, suburban and rural fire departments also deal with other common types of fires including vehicle fires, trash fires, and small debris or vegetation fires. For 2011, NFPA estimates for total fire department responses to fires are as summarized below in Table 9-2. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-3

100 9.2.2 Wildland Fires Table 9.2: 2011 NFPA Fire Statistics Type of Fire Fire Department Responses Structure Fire 484,500 Vehicle Fire 219,000 Fires Outside Structures 79,000 Rubbish Fires 180,500 Wildland Fires 338,000 All Other Fires 88,500 TOTAL 1,389,500 The complete NFPA fire statistics estimates are given in their report Fire Loss in the United States During Data available from the NFPA website at Wildland fires are fires where vegetation (grass, brush, or trees) is the primary fire fuel. Wildland fires in Oregon typically occur in national or state forests and parks or in forest tracts of private land that may be owned by forest industries or by other private owners. By definition, wildland fires generally involve few or no structures. Fires that involve a mixture of vegetation and structures are considered wildland/urban interface fires and are discussed below in Section Fire suppression strategy for wildland fires is significantly different than for structure fires. For wildland fires, the most common suppression strategy is to contain the fire at its boundaries, to stop the spread of the fire and then to let the fire burn itself out. Fire containment typically relies heavily on natural or manmade fire breaks. Water and chemical fire suppressants are used primarily to help make or defend a fire break, rather than to put out an entire fire, as would be the case with a structure fire. Fires that are purely wildland fires, without threatening structures, nevertheless cause environmental and ecological damage. Wildland fires kill wildlife and damage habitat. Areas that have burned are also subject to erosion and landslides due to loss of ground cover. Such fires also may result in large fire suppression costs, with a potential for casualties among firefighting personnel. Historically, fire suppression strategy for wildland fires has generally been to try to minimize the acreage burned in each wildland fire, by applying the maximum available fire suppression resources and trying to contain each fire as quickly as possible. In recent years, however, fire suppression strategy for wildland fires has evolved substantially in two important aspects. First, to a greater extent than previously, wildland fires are being recognized as part of the natural ecology and natural life cycles of wildlands. Fires create open spaces with different habitats for both plants and animals than existed previously. Second, the emphasis on maximum suppression of wildland fires has resulted in many fires being smaller than would naturally occur. Because of the reduction in frequent, smaller City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-4

101 fires, many wildland areas have developed extraordinarily high fuel loads. Thus, the potential for very large, catastrophic wildland fires may actually be increased by the effective suppression of smaller fires. In recent years, evolving strategies for dealing with wildland fires have focused more attention on fuel management. Strategies include more controlled burns and greater tolerance for allowing smaller fires to burn, with the objective of reducing fuel loads of smaller vegetation and thus reducing the potential for larger fires. Wildfires may be started by natural causes, such as lightning strikes. US Forest Service data indicate that nearly 14% of wildfires are started by lightning. About 25% of wildfires are arson, while the rest are due to a variety of manmade causes including debris burns, discarded smoking materials, sparks from vehicles, sparks from power lines, and so on. Wildfire hazard depends on three main factors: vegetative fuel load, weather, and topography. Vegetative Fuel Load. There are several parameters that define the fire potential of vegetation. Vegetative fuel loads are typically expressed as tons per acre: the greater the fuel loading, the greater the amount of energy that will be released in a fire. Vegetative fuels are also classified by burn index, which is a measure of the amount of energy per pound of fuel. Fuels may also be classified by potential duration of burning. For example, wildfires fueled by grass may spread very quickly, but grass contains relatively little fuel energy and tends to burn out quickly. Wildfires fueled by larger vegetation may spread more slowly, but larger vegetation contains more fuel energy and tends to burn for a longer duration. Moisture Content. Moisture content of vegetative fuels is also a major determinant of wildland fire potential. The lower the moisture content the greater the fire potential. Moisture content at any given time depends on antecedent (before the given time) weather conditions. The moisture content of larger fuels (e.g., trees) depends on previous weather conditions over periods of several weeks or even months. The moisture content of smaller fuels (brush) depends on previous weather conditions over several days or a week or two. The moisture content of very small fuels (e.g., grasses) depends largely on previous weather conditions over a few hours or a day or two. Fuel Continuity. The fire hazard posed by vegetative fuel loads also depends on fuel continuity, both horizontally and vertically. Horizontal continuity, the distribution of fuels over the landscape, strongly affects the spread and containment of wildfires in a given geographic area. Vertical continuity of fuels, the linkage between fuels at ground level and tree crowns, also affects the fire potential. Forests with strong ladder fuels (understory growth between ground fuels and tree crowns) are more likely to have major fires involving tree crowns. Forests with limited ground fuels and little or no ladder fuels are much more likely to experience minor ground fires without a fire involving tree crowns. Weather. Weather also has a profound impact on wildland fire potential. Weather conditions of high temperatures, low humidity, and high winds may greatly accelerate the spread of a wildland fire and make containment difficult or impossible. Changes in weather conditions can greatly accelerate a fire s spreading rate. Many casualties have occurred when firefighting personnel are trapped by sudden bursts of fire spread in response to changes in wind conditions. For many larger fires, containment is possible only with a little help from Mother Nature via lower temperatures, reduced winds or significant rainfall. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-5

102 Topography. Local topography is also a major factor in the spread of wildfires. Fires burn much more quickly up slope than they do down slope. Doubling a slope approximately doubles the rate of fire spread. Canyons, gulches and other local topographic effect can act as chimneys, intensifying fires in certain areas. Fires tend to slow at ridge tops and thus ridge tops are often chosen as locations for fire breaks. Suppression of wildland fires depends on the three main factors - vegetative fuel load, weather, and topography - that, in combination, govern fire potential. High fuel loads, hot, dry, windy weather and steep slopes increase fire potential and make fire suppression much more difficult. Conversely, low fuel loads, cool, moist weather with low winds, and gentle slopes make fire suppression easier. In addition, however, fire suppression also depends on two other important factors: availability of fire suppression resources and access. Fire suppression resources include firefighting personnel, equipment and apparatus, as well as water and chemical fire suppressants. The greater the availability of fire suppression resources, the more likely it is that a given fire will be contained quickly. Fire suppression also depends on access. Fires in remote areas without ground access via roads are more difficult to fight and thus harder to contain than are fires with better access for fire suppression crews and apparatus. In the 1930s, wildfires consumed an average of 40 to 50 million acres per year in the contiguous United States, according to US Forest Service estimates (US Forest Service, Managing the Impact of Wildfires on Communities and the Environment, September 8, 2000). By the 1970s, the average acreage burned had been reduced to about 5 million acres per year. Over this time period, fire suppression efforts were dramatically increased and firefighting tactics and equipment became more sophisticated and effective. In 2011, nearly 9 million acres burned in wildfires. However, because of this pattern of more effective suppression of wildland fires, the patterns and characteristics of wildland fires are changing. Vegetation species that would have normally been minimized by frequent fires became more dominant. Over time, many species have become susceptible to disease and insects, leading to an increase in dead and dying trees. The resulting accumulation of debris has created the types of fuels than promote intense, rapidly spreading fires. In many areas introduction of non-native species has also added to the fuel load. Decades old patterns of logging and fire suppression have also changed the characteristics of forests. Older forests were typically less dense, with smaller numbers of larger, more fire-resistant trees. Newer forests are denser with larger numbers of smaller less fire-resistant trees. In combination these effects over the last several decades have resulted in many recent wildland fires that are hotter, faster, and larger than those experienced in the past Wildland/Urban Interface Fires Wildland/urban interface fires are fires where the fuel load consists of both vegetation and structures. In Oregon, as elsewhere in the United States, recent patterns of development have lead to increasing numbers of homes being built in areas subject to wildland fires. Development in areas subject to wildland fires may pose high levels of life safety risk for occupants as well as high levels of fire risk for homes and other structures. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-6

103 Urban or suburban areas may have a significant amount of landscaping and other vegetation. However, in such areas the fuel load of flammable vegetation is not continuous, but rather is broken by paved areas, open space and areas of mowed, often irrigated, grassy areas with low fuel loads. In these areas, the vast preponderance of all significant fires is single structure fires. The combination of separations between buildings, various types of fire breaks, and generally low total vegetative fuel loads make the risk of fire spreading much lower than in wildland areas. Furthermore, most developed areas in urban and suburban areas have water systems with good capacities to provide water for fire suppression and organized fire departments who typically respond quickly to fires, with sufficient personnel and apparatus to control fires effectively. Thus, in such areas the risk of a single structure fire spreading to involve multiple structures is generally quite low. Areas subject to wildland/urban interface fires have very different fire hazard characteristics. The defining characteristic of the wildland/urban interface area is that structures are built in areas with essentially continuous (and often high) vegetative fuel loads. In other words, structures are built in areas subject to wildland fires. When wildland fires occur in such areas, they tend to spread quickly and structures in these areas may, unfortunately, become little more than additional fuel sources for wildland fires. The fire risk is to structures and occupants in wildland/urban interface areas is high not only because of the high vegetative fuel loads but also because fire suppression resources are typically much lower than in urban or suburban areas. Homes in wildland/urban interface areas are most commonly on wells rather than on municipal water supplies. Thus, the availability of water for fire suppression is often severely limited. Less availability of water resources makes it more likely that a small wildland fire or a single structure fire in an urban/wildland interface area will spread before it can be extinguished. Furthermore, because many developments in interface areas have relatively low populations and are some distance from population centers, the availability of firefighting personnel and apparatus is generally lower than in more populated areas and response times are typically much longer. The longer typical response times arise in part because of greater travel distances and, thus, greater travel times, but also because most fire departments in lower population density areas are entirely or largely composed of volunteer staff. Response times from volunteer staff fire departments are typically longer than response times for career staff departments, where fire stations are commonly staffed continuously. In some cases, narrow winding roads also impede access by fire fighting apparatus. As with water supplies, the lower availability of fire fighting personnel and apparatus and the longer response times increase the probability that a small wildland fire or a single structure fire in an urban/wildland interface area will spread before it can be extinguished. Developments in urban/wildland interface areas often face high fire risk because of the combination of high fire hazard (high vegetative fuel loads) and limited fire suppression capabilities. Unfortunately, occupants in many wildland/urban interface areas also face high life safety risk. High life safety risk arises because of the high fire risk, especially from large fires that may spread quickly and block evacuation. Life safety risk in interface areas is often exacerbated by limited numbers of roads (in the worst case only one access road) that are often narrow and winding and subject to blockage by a wildland fire. Life safety risk in interface areas is also often exacerbated by homeowners reluctance to City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-7

104 evacuate homes quickly. Instead, homeowners often try to protect their homes with whatever fire suppression resources are available. Such efforts generally have very little effectiveness. For example, the water flow from a garden hose is too small to meaningfully impact even a single structure fire (once the structure is significantly engulfed by flames) and is profoundly too small to have any impact on a wildland fire. Unfortunately, home owners who delay evacuation in well meant but misguided attempts to save their homes often place their lives in grave jeopardy by delaying evacuation until it may be impossible. Major fires in the urban/wildland interface have the potential for enormous destruction and very high casualties. For example, the October 20, 1991 East Bay Fire in Oakland California burned 1,600 acres with 25 fatalities, 150 injuries, and over 3300 single-family homes and 450 apartment units destroyed. Total damages were over $1.5 billion. This fire was fueled by very high vegetative fuel loads and occurred on an unusually hot, dry, windy day. The fire spread extremely quickly, with over 800 homes engulfed by fire within the first hour, and completely overwhelmed initial fire suppression efforts. In October 1991, rural counties near Spokane Washington experienced 92 separate fires that burned about 35,000 acres and 114 homes. Between October 25 and November 3, 1993, 21 major wildland fires broke out in California. These fires burned over 189,000 acres and destroyed over 1,100 structures with 3 fatalities and hundreds of injuries. The worst wildland/urban interface fire in United States history as far as casualties are concerned occurred in 1871 in Peshtigo, Wisconsin. This fire burned over 1.2 million acres and killed over 1,200 people. In 2003, a series of wildland/urban interface fires in southern California burned over 750,000 acres and destroyed over 3,000 homes. These few examples dramatically illustrate the potential for disasters in the urban/wildland interface area. 9.3 Measures of the Level of Fire Hazard There are several quantitative and semi-quantitative measures of the level of fire hazard. Most of these measures have been developed by the United States Forest Service in cooperation with other fire agencies. National maps of these fire hazard measures are available at the Forest Service website ( These maps are updated very frequently, in some cases daily. All of the Forest Service Fire Danger maps and related technical maps are viewable at the website by going to the INDEX category, then to Fire, Wildland Fire Assessment System. The spatial resolution of the web-published maps is relatively low. For example, the Oregon data are based on about 90 reporting stations scattered across the state. Thus, these maps are intended to show regional differences in the level of fire hazard, rather than detailed local differences. However, as a regional guide to fire hazard levels, these maps are enormously useful and readily accessible. The most useful major fire danger measures are briefly reviewed below. For reference, we note that the Forest Service website also has an extensive glossary of fire-related terms, which may be helpful for those unfamiliar with fire terminology and nomenclature Observed Fire Danger Class Maps Fire danger class is a four level fire danger classification scheme that is based largely on moisture content in fuels and weather conditions (temperature, humidity, wind). Daily nationwide maps are viewable and printable from the Forest Service website ( This fire danger classification is widely used for purposes such as restricting City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-8

105 campfires and outdoor burning and is widely reported in the media. The formal definitions of the four levels of danger are given below. LOW: Fuels do not ignite readily from small firebrands, although more intense heat sources, such as lightning, may start many fires in duff or punky wood. Fires in open cured grassland may burn freely a few hours after rain, but woods fires spread slowly by creeping or smoldering, and burn in irregular fingers. There is little danger of spotting. The color code is green. MEDIUM: Fires can start from most accidental causes, but with the exception of lightning fires in some areas, the number of starts is generally low. Fires in open-cured grassland will burn briskly and spread rapidly on windy days. Woods fires spread slowly to moderately fast. The average fire is of moderate intensity, although heavy concentrations of fuel, especially draped fuel, may burn hot. Short-distance spotting may occur, but is not persistent. Fires are not likely to become serious, and control is relatively easy. The color code is blue. HIGH: All fine dead fuels ignite readily and fires start easily from just causes. Unattended brush and campfires are likely to escape. Fires spread rapidly and short-distance spotting is common. High-intensity burning may develop on slopes, or in concentrations of fine fuel. Fire may become serious and their control difficult, unless they are hit hard and fast while small. The color code is yellow. EXTREME: Fires under extreme conditions start quickly, spread furiously, and burn intensely. All fires are potentially serious. Development into highintensity burning will usually be faster and occur from smaller fires than in the very high danger class. Direct attack is rarely possible, and may be dangerous, except immediately after ignition. Fires that develop headway in heavy slash or in conifer stands may be unmanageable while the extreme burning condition lasts. Under these conditions, the only effective and safe control action is on the flanks until the weather changes or the fuel supply lessens. The color code is red Fire Potential Index Map This experimental product portrays a more quantitative measure of fire danger than the Fire Danger Classification map discussed above. This map is primarily of interest for fire service professionals and fire researchers Other Maps The Forest Service website also provides several other types of technical maps which are intended for fire service professionals and fire researches. These maps and all of the more common maps summarized above can also be found at the FDR (Fire Danger Rating) web page which can be accessed via the search button on the Forest Service Home Page referenced above. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-9

106 9.4 Historical Data for Wildland Fires in Oregon The Oregon Department of Forestry website ( has a table of the most important historical fires in Oregon over the past 150 years. Of these 12major fires, the five largest fires all occurred between 1848 and The two largest fires, the 1865 Silverton fire and the 1849 Siletz fire consumed 988,000 and 800,000 acres of wildland, respectively. The 1933 Tillamook fire burned 240,000 acres. Since 1945, the two largest fires, the 1945 Wilson River/Salmonberry fire and the 1987 Silver fire, consumed 180,000 and 97,000 acres, respectively. None of these major fires occurred in Linn County. The Oregon Department of Forestry website ( has fire suppression responsibility for nearly 16 million acres in Oregon The 10-year average number of fires in ODF-protected areas from January 1, 2004 to July 31, 2013 is 454, with an annual average of 14,513 acres burned. However, the number of fires and the acres burned have been much higher than average both in 2013 and in 2014 through July 31, 2014 with the number of fires being 588 and 571, and the acres burned being 81,230 and 51,541 for the 2013 and 2014 time periods, respectively.. The United States Forest Service (Department of Agriculture), in cooperation with several agencies from the Department of the Interior, published a report in 2001 identifying wildland/urban interface communities within the vicinity of Federal lands that are a high risk from wildfire (Federal Register, Volume 66, Number 3, pages , January 4, 2001). For Oregon, these identified high-risk communities and areas did not include Sweet Home or any communities in Linn County. The Oregon Department of Forestry website ( has an excellent map showing forest coverage and forest type throughout Oregon. Oregon Department of Forestry data on forest ownership areas are shown below in Table 9-3 for Oregon as a whole. Table 9-3: Forest Land Ownership in Oregon Ownership Acres Percent of Total Federal 15,968, % State 885, % Other Public Lands 123, % Tribal 414, % Forest Industry 5,870, % Other Private 4,506, % Total 27,766, % For Oregon as a whole, about 61% of the forest lands are public, 1.5% are tribal, with the remainder being privately owned. Of the privately owned forest land, about 57% is owned by the forest industry. Statewide, the Oregon Department of Forestry has responsibility for about 15.8 million acres of forest land, or about 57% of the total forests in Oregon. The overall forest ownership pattern for Linn County appears to be roughly similar to the statewide pattern shown above. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-10

107 9.5 Urban/Wildland Interface Fire Hazards for Sweet Home The eastern portion of Linn County is heavily forested, including the Willamette National Forest and privately owned lands. As shown in Map 9-1 above, much of the lands to the north, east, and south of Sweet Home are forested with interspersed blocks of recently cut forest Overview and Background Information As discussed above in Section 9.1, wildland/urban interface fires are wildland fires in areas where structures provide additional fuel load. Thus, the fire hazard for wildland/urban interface fires is essentially the same as the fire hazard for wildland fires. In this context, fire hazard means the probability and severity of fires. Fire risk, the threat to people and the built environment, depends on the level of fire hazard and on the extent of development in fire-prone areas. The three primary factors governing the level of hazard for wildland fires or wildland/urban interface fires are: fuel load, weather and topography. For Sweet Home, the fuel load in the nearby forested areas is generally high and relatively continuous across large geographic areas. Because of historical logging activities, much of the forest is composed of relatively young trees, with a high density of trees per acre. Such forests may pose a higher fire hazard than do old growth forests with fewer, larger trees. Topography contributes to fire hazard because fires spread much more quickly up steep slopes. Weather is very important in governing the level of fire hazard. Rainfall amounts and patterns contribute to the level of fuel load and also to moisture levels in vegetation. During fires, temperature, humidity and wind speed are major factors governing the rate of spread of wildland fires and thus major factors governing the ease or difficulty with which a given fire is likely to be contained. Typical annual rainfall amounts for Sweet Home are moderately high to high, with annual rainfall of about 54 inches. Fire hazards near Sweet Home would be highest during prolonged periods of drought, especially after periods of normal to above normal rainfall, which would result in a combination of high fuel loads and unusually dry conditions Historical Fire Data for Linn County and Sweet Home ODF data for wildland or wildland/urban interface areas where fire protection is provided by ODF are shown in the following tables for the time period from 2000 to During this time period there were a total of 396 fires, an average of about 26 fires per year. During this time period the total acres burned was about 1,686, an average of about 107 acres per year. However, nearly 2/3rds of the acres burned occurred in one fire, the September 1, 2005 fire listed as the Middle Fork Fire in the ODF database. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-11

108 Table 9-4: Wildland and Wildland/Urban Fires in Linn County in ODF Protection Areas ( ) Fuel Class Fuel Class Description Number of Fires Percent of Fires A Annual grasses % B Dense Chaparral % C Open pine, grass under % F Dense Brush (lighter than B) % G Conifer, Old growth % H Conifer, Second growth % I Slash, heavy % J Slash, medium % K Slash, thinning, P.C., Scattrd % L Grass Perennial % R Hardwood, summer % T Sagebrush, medium dense % U Closed canopy pine % X Non wildland fuel % Totals % Table 9-5: Wildland and Wildland/Urban Fires in Linn County in ODF Protection Areas ( ) Fire Size (Acres) Number of Fires < to to to Table 9-6: Wildland and Wildland/Urban Interface Fires Responded to by the Sweet Home Fire and Ambulance District (SHFAD), 2012 Fire Type SHFAD Acres brush or brush and grass mix 6 3 forest or woods grass 0 0 vegetation fire, other 2 0 TOTAL Source: Mike Beaver, Chief of the Sweet Home Fire and Ambulance District City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-12

109 There are several reasons why the fire risk may be higher than suggested by the Linn County and Sweet Home data above, especially in developing wildland/urban interface areas: 1) Large fires may occur infrequently, but statistically they will occur. One large fire could significantly change the statistics. The level of fire hazard depends profoundly on weather patterns. A several year drought period would substantially increase the probability of large wildland fires in Linn County. For smaller vegetation areas, with grass, brush and small trees, a much shorter drought period of a few months or less would substantially increase the fire hazard. 2) The level of fire hazard in wildland/urban interface areas, with the greatest risk for life safety and property, is likely significantly higher than for wildland areas Linn County as a whole. The probability of fires starting in interface areas is higher than in wildland areas because of the much higher population density in interface areas. Most wildland or interface fires have human sources of ignition - arson, sparks from vehicles or electric lines, discarded smoking materials, or trash or debris fires that get out control, and so on. Thus, the probability of a given acre burning is higher in interface areas than for the wildland areas of Linn County as a whole. Development (e.g., homes and other buildings with accompanying infrastructure) in wildland/urban interface areas face a range of levels of fire risk, depending on a number of factors. Developments that have all of most of the following attributes are at the highest level of risk: 1) High vegetative fuel loads, with a high degree on continuity of fuel load (i.e., few significant firebreaks). Risk may be particularly high if the fuel load is grass, brush and smaller trees, subject to being at very low moisture levels in short duration drought periods. 2) Higher slopes, which cause fires to spread more rapidly than in flatter terrain, 3) Limited fire suppression capacity, including limited water supply capacity for fire suppression purposes, limited fire fighting personnel and apparatus, and typically long response times for fire alarms, 4) Limited access for firefighting apparatus and limited evacuation routes for residents at risk, 5) Construction of structures to less than fully fire-safe practices, and 6) Lack of maintenance of firebreaks and defensible zones around structures. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-13

110 Overall, for eastern Linn County, including the vicinity of Sweet Home, the threat of wildland fire and/or wildland/urban interface fires appears moderate, in large part because of the typically high levels of rainfall. However, depending on specific conditions in developments in wildland/urban interface areas, the threat may be moderate to high, especially during periods of drought. The specific level of risk for each development depends on the particular risk factors as summarized above. A comprehensive evaluation of the level of risk for developments in wildland/urban interface areas requires a specific evaluation of the risk attributes listed above for each development area. A review of topography, forest cover and development patterns for Sweet Home suggest that the following portions of Sweet Home have higher levels of risk for wildland/urban interface fires than the City as a whole: 1) northeast Sweet Home, west of Foster Lake, south of the Mark s Ridge area, and 2) southern Sweet Home, especially the newer developments that extend into the forested areas, including the Lake Pointe and Canyon Creek subdivisions. The potential impacts of wildland/urban interface fires on Sweet Home are summarized below in Table 9-7. Table 9-7: Potential Impacts of Wildland/Urban Interface Fires on Sweet Home Inventory Portion of Sweet Home Affected Buildings Streets within Sweet Home Roads to/from Sweet Home Electric Power Other Utilities Casualties Probable Impacts Highest risk areas are residential areas bordering heavily vegetated wildland areas as shown on Map 9-1 and discussed above in Section 9.4. Small wildland/urban interface fires could affect a few residential buildings. Larger fires could affect entire neighborhoods and extreme events (cf. Oakland Hills 1991 Fire) could affect hundreds of buildings. Minor road closures possible from fires; limited impact because of short detour routes within Sweet Home. Potential closures of major highways due to fires, especially roads into the Cascades. Potential for localized loss of electric power due to fires affecting power lines in or near Sweet Home. Generally minor or no impacts from fires, except for possible loss of telephone service due to fires affecting phone poles and/or lines. Potential for deaths and injuries in major wildland/urban interface fires, especially if evacuations are not completed expeditiously. 9.6 Wildland/Urban Interface Fire Events Since 2009 There have been no significant wildland/urban interface fire events in or near Sweet Home since the completion of the 2009 update of the SHMP. 9.7 Mitigation Strategies This section outlines suggested strategies for reducing the level of risk to both property and life safety in wildland/urban interface development areas that may be at high risk from wildland/urban interface fires. The suggested mitigation strategy has four elements: 1) reduce the probability of fire ignitions, 2) reduce the probability that small fires will spread, City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-14

111 3) minimize property damage, and 4) minimize the life safety risk Reduce the Probability of Fire Ignitions Efforts to reduce the probability of fire ignitions should focus on manmade causes of ignition through a combination of fire prevention education, enforcement, and other actions. Fire prevention education actions could include efforts to heighten public awareness of fire dangers, especially during high danger time periods and better education about fire safe practices, such as careful disposal of smoking materials, and adhering to restrictions on burning of rubbish and debris. Fire prevention enforcement action could include strict enforcement of burning restrictions and vigorous investigation and prosecution of arson cases. An important physical action to reduce the probability of ignitions is to maintain or upgrade tree-trimming operations around power lines to minimize fires starting by sparking from lines to vegetative fuels Reduce the Probability that Small Fires Will Spread Possible mitigation actions to reduce the probability that small fires will spread include enhancement of water supply and fire suppression capabilities for high risk areas, expansion of existing firebreaks, creation of new firebreaks and expanding defensible spaces around structures in wildland/urban interface areas Minimize Property Damage The education and action items discussed above may help to reduce future property damages by reducing the number of fire ignitions and by reducing the probability that a small fire will spread. In addition, specific fire safe building practices should be implemented (if not yet implemented) or enforced vigorously (if not yet vigorously enforced). Fire safe building practices have two main elements: first, design of structures, and second, creation of defensible spaces around structures. The National Fire Protection Association (NFPA) has an excellent Firewise communities program with an excellent, highly informative website ( The firewise website can also be reached from the main NFPA website ( The Firewise website has very informative publications and videos for local officials and homeowners to help understand, evaluate, and improve the fire safety of structures at risk from wildland/urban interface fires. The firewise construction and firewise landscaping checklists are particularly recommended as concise summaries of the primary fire-safe designs and practices for homeowners at risk from wildland/urban interface fires. The NFPA s Firewise Construction Checklist, makes the following main recommendations (among others): 1) Site homes on as level terrain as possible, at least 30 feet back from cliffs or ridge lines. 2) Build homes with fire-resistant roofing materials, such as Class-A asphalt shingles, slate or clay tiles, concrete or cement products, or metal. 3) Build homes with fire-resistant exterior wall cladding, such as masonry or stucco. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-15

112 4) Consider the size and materials for windows; smaller panes hold up better than larger ones, double pane and tempered glass windows are more fire resistant than single pane windows; plastic skylights can melt and allow access for burning embers. 5) Prevent sparks and embers from entering vents by covering vents with wire mesh no larger than 1/8", box eaves, and minimize places to trap embers on decks and other attached structures. 6) Keep roofs, eaves, and gutters free of flammable debris. The NFPA s Firewise Landscaping Checklist includes the following main recommendations (among others), based on a four-zone planning concept around the house: 1) Zone 1 should be well irrigated area of closely mowed grass or nonflammable landscaping materials such as decorative stone, at least 30' in all directions around the home. 2) Zone 2 should be a further irrigated buffer zone with only a limited number of low-growing, fire-resistant plants. 3) Zone 3, further from the house, can include low growing plants and wellspaced, well-pruned trees, keeping the total vegetative fuel load as low as possible. 4) Zone 4 is the natural area around the above three landscaped zones. This area should be thinned selectively, with removal of highly flammable vegetation and removal of ladder fuels that can spread a grass fire upwards into tree tops Minimize Life Safety Risk The mitigation actions above may help to minimize life safety risk by helping to reduce the number of ignitions, by reducing the probability that small fires will spread, and by encouraging more fire-safe practices of building construction and fire-safe landscaping. These practices are meritorious for reducing the fire hazards to structures. However, they may also give homeowners a false sense of life safety security. A false sense of security may encourage people to stay in homes at risk during wildfires, rather than evacuating immediately at the first fire warning. The most important action to minimize life safety risk during wildland/urban interface fires is immediate evacuation. Thus, reducing life safety risk requires public education and emergency planning to encourage and expedite warnings and evacuations (voluntary or mandatory). Life safety risk during wildland/urban interface fires is exacerbated by limited evacuation routes. Improving evacuation roads (widening, straightening) and, most importantly, providing as many alternate evacuation routes as possible can significantly reduce evacuation times and lower the probability that residents seeking to evacuate may be trapped by fire-blocked routes. The Table 9-8 contains wildland/urban interface fire mitigation action items from the master Action Items in Chapter 4. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-16

113 OG OG OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 9-8: Wildland/Urban Interface Fire Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx Wildland/Urban Interface Mitigation Action Items ST #1 Identify and map evacuation routes and procedures for high risk areas, disseminate and educate the public. CE; SHPD; SHFAD; ODF City, FEMA, ODF, SHFAD X X X LT #1 Encourage fire-safe construction practices for existing and new construction in high risk areas. SHMPC; CCDD; SHFAD; ODF City, FEMA, ODF, SHFAD X X X X X LT #2 Continue fuels reduction projects and public education for the high hazard areas of SH identified previously. Initial work has been done, but continuing efforts necessary since fuels grow back. SHFAD; ODF City, FEMA, ODF, SHFAD X X X X Same as Table 4-5 in Chapter 4, page 4-9. G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 9-17

114 10.0 EARTHQUAKES 10.1 Overview and Earthquake Primer Overview Historically, awareness of seismic risk in Oregon has generally been low, among both the public at large and public officials. This low level of awareness reflected the low level of seismic activity in Oregon, at least in recent historical time. However, over the past several years, awareness of seismic risk in Oregon has significantly increased. Factors in this increased awareness include the 1993 Scotts Mills earthquake in Clackamas County, widespread publicity about possible large magnitude earthquakes on the Cascadia Subduction Zone, and recent changes in Seismic Zonation in the Oregon Building Code which increased seismic design levels for new construction in western Oregon. Before reviewing the levels of seismic hazard and seismic risk in Linn County and Sweet Home, we first present a brief earthquake primer that reviews some basic earthquake concepts and terms Primer In the popular press, earthquakes are most often described by their Richter Magnitude (M). Richter Magnitude is a measure of the total energy released by an earthquake. In addition to Richter magnitude, there are several other measures of earthquake magnitude used by seismologists, but such technical details are beyond the scope of this discussion. The Scotts Mills (Oregon) earthquake was M = 5.6, while the Northridge (California) earthquake was about M = 6.7. Great earthquakes, for example, on the San Andreas Fault or on the Cascadia Subduction Zone, may have magnitudes of 8 or greater. It is important to recognize that the Richter scale is not linear, but rather logarithmic. A M8 earthquake is not twice as powerful as a M4, but rather thousands of times more powerful. A M7 earthquake releases about 30 times more energy that a M6, while a M8 releases about 30 times more energy than a M7 and so on. Thus, great M8 earthquakes may release thousands of times as much energy as do moderate earthquakes in the M5 or M6 range. The public often assumes that the larger the magnitude of an earthquake, the worse the earthquake. Thus, the big one is the M8 earthquake and smaller earthquakes (M6 or M7) are not the big one. However, this is true only in very general terms. Larger magnitude earthquakes affect larger geographic areas, with much more widespread damage than smaller magnitude earthquakes. However, for a given site, the magnitude of an earthquake is NOT a good measure of the severity of the earthquake at that site. Rather, the intensity of ground shaking at the site depends on the magnitude of the earthquake and on the distance from the site to the earthquake. An earthquake is located by its epicenter - the location on the earth s surface directly above the point of origin of the earthquake. Earthquake ground shaking diminishes (attenuates) with distance from the epicenter. Thus, any given earthquake will produce the strongest ground motions near the earthquake with the intensity of ground motions diminishing with increasing distance from the epicenter. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-1

115 Thus, for a given site, a smaller earthquake (such as a M6.5) which is very close to the site could cause greater damage than a much larger earthquake (such as a M8) which is quite far away from the particular site. However, earthquakes at or below M5 are not likely to cause significant damage, even locally very near the epicenter. Earthquakes between about M5 and M6 are likely to cause some damage very near the epicenter, with the extent of damage typically being relatively minor (e.g., the 1993 Scotts Mills earthquake). Earthquakes of about M6.5 or greater can cause major damage (e.g., the Northridge earthquake), with damage usually concentrated fairly near the epicenter. Larger earthquakes of M7+ cause damage over increasingly wider geographic areas with the potential for very high levels of damage near the epicenter. Great earthquakes with M8+ can cause major damage over wide geographic areas. For example, a M8+ on the Cascadia Subduction Zone could affect the entire Pacific Northwest from British Columbia, through Washington and Oregon, and as far south as Northern California. The intensity of ground shaking varies not only as a function of M and distance but also depends on soil types. Soft soils may amplify ground motions and increase the level of damage. Thus, for any given earthquake there will be contours of varying intensity of ground shaking. The intensity will generally decrease with distance from the earthquake, but often in an irregular pattern, reflecting soil conditions (amplification) and possible directionality in the dispersion of earthquake energy. There are many measures of the severity or intensity of earthquake ground motions. A very old, but commonly used, scale is the Modified Mercalli Intensity scale (MMI), which is a descriptive, qualitative scale that relates severity of ground motions to types of damage experienced. MMIs range from I to XII. More useful, modern intensity scales use terms that can be physically measured with seismometers, such as the acceleration, velocity, or displacement (movement) of the ground. The most common physical measure, and the one used in the Mitigation Plan and in the Technical Appendix, is Peak Ground Acceleration or PGA. PGA is a measure of the intensity of shaking, relative to the acceleration of gravity (g). For example, 1.0 g PGA in an earthquake (an extremely strong ground motion) means that objects accelerate sideways at the same rate as if they had been dropped from the ceiling. 10% g PGA means that the ground acceleration is 10% that of gravity and so on. Damage levels experienced in an earthquake vary with the intensity of ground shaking and with the seismic capacity of structures. Ground motions of only 1 or 2% g are widely felt by people; hanging plants and lamps swing strongly, but damage levels, if any, are usually very low. Ground motions below about 10% g usually cause only slight damage. Ground motions between about 10% g and 30% g may cause minor to moderate damage in well-designed buildings, with higher levels of damage in poorly designed buildings. At this level of ground shaking, only unusually poor buildings would be subject to potential collapse. Ground motions above about 30% g may cause significant damage in well-designed buildings and very high levels of damage (including collapse) in poorly designed buildings. Ground motions above about 50% g may cause high levels of damage in most buildings, even those designed to resist seismic forces. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-2

116 10.2 Seismic Hazards for Linn County and Sweet Home Earthquakes in Western Oregon, and throughout the world, occur predominantly because of plate tectonics - the relative movement of plates of oceanic and continental rocks that make up the rocky surface of the earth. Earthquakes can also occur because of volcanic activity and due to other geologic processes. The earthquake hazard for Benton, Lane and Linn Counties is reviewed in detail in Chapter 3 of the Regional Mitigation Plan, Phase Two Technical Appendix, Benton, Lane and Linn Counties Oregon, Seismic Loss Potential (2001). The main findings of that chapter are briefly summarized below. The Cascadia Subduction Zone is a geologically complex area off the Pacific Northwest coast from Northern California to British Columbia. In simple terms, several pieces of oceanic crust (the Juan de Fuca Plate, Gorda Plate and other smaller pieces) are being subducted (pushed under) the crust of North America. This subduction process is responsible for most of the earthquakes in the Pacific Northwest as well as for creating the volcanoes in the Cascades. Figure 10-1 shows the geologic (plate-tectonic) setting for Oregon. There are three source regions for earthquakes that can affect the Sweet Home area: 1) interface earthquakes on the boundary between the subducting oceanic plates and the North American plate, 2) intraslab or intraplate earthquakes within the subducting oceanic plates, and 3) crustal earthquakes within the North American Plate. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-3

117 The geographic and geometric relationships of these earthquake source zones are shown in Figure A full discussion of current understanding of these subduction zone and crustal earthquakes is given in Chapter 3 of the Regional Mitigation Plan (2001 Phase Two Technical Appendix, Benton, Lane and Linn Counties Oregon, Seismic Loss Potential). The interface earthquakes on the Cascadia Subduction Zone may have magnitudes of 8 or greater, with probable recurrence intervals of 500 to 800 years. The last major earthquake in this source region probably occurred in the year 1700, based on current interpretations of Japanese tsunami records. Such earthquakes are the great Cascadia Subduction Zone earthquake events that have received attention in the popular press. These earthquakes occur at about 20 to 60 kilometers (12 to 40 miles) offshore from the Pacific Ocean coastline. Ground shaking from such earthquakes would be very strong near the coast and moderately strong ground shaking would be felt throughout Linn County, with the level of shaking decreasing towards eastern Linn County. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-4

118 The intraslab earthquakes, which are also called intraplate earthquakes, occur within the subducting oceanic plate. These earthquakes may have magnitudes up to about 7.5, with probable recurrence intervals of about 500 to 1000 years (recurrence intervals are poorly determined by current geologic data). These earthquakes occur quite deep in the earth, about 30 or 40 kilometers (18 to 25 miles) below the surface with epicenters that would likely range from near the Pacific Ocean coast to about 50 kilometers (30 miles) inland. Thus, epicenters from these types of earthquakes could be located in Lincoln County or western Lane County or possibly in western Benton County. Ground shaking from such earthquakes would be very strong near the epicenter and moderately strong ground shaking would be felt throughout all of Linn County, with the level of shaking decreasing towards eastern Linn County. Crustal earthquakes within the North American plate are possible on faults mapped as active or potentially active as well as on unmapped (unknown) faults. Historically observed crustal earthquakes in Northern Oregon from 1973 to 2012 are shown in Figure During this time period, several dozen, mostly small, earthquakes have occurred in Linn County. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-5

119 Section 3.3 of the Phase Two Technical Appendix (2001 Regional Mitigation Plan 2001) discusses the current geologic knowledge about crustal faults in the three county area. Several faults have been mapped in the area, especially in Benton and Lane Counties. In the Willamette Valley, the geological processes of erosion and deposition have obliterated most of the possible evidence for past surface fault ruptures. In the three county area, the mapped faults are generally considered to be inactive, with no evidence for activity within the past 11,000 years. Based on the historical seismicity in Western Oregon and on analogies to other geologically similar areas, small to moderate earthquakes up to M5 or M5.5 are possible almost anyplace in Western Oregon, including almost anyplace in Linn County. Such earthquakes would be mostly much smaller than the Scotts Mills earthquake up to about the magnitude of that 1993 earthquake. The possibility of larger crustal earthquakes in the M6+ range cannot be ruled out. However, in the absence of known, mapped faults, the probability of such events is likely to be very low. Because the probability of large crustal earthquakes (M6 or greater) affecting Linn County is so low and because any damage in smaller crustal earthquakes is likely to be minor and very localized, crustal earthquakes are not considered significant for hazard mitigation planning purposes. Therefore, our analysis focuses on the larger, much more damaging earthquakes arising from the Cascadia Subduction Zone. The characteristics of the subduction zone earthquakes affecting Linn County are summarized in Table 10-1 below. The maximum magnitudes are estimated from the length and width of the mapped fault plane or from similar earthquakes elsewhere in the Pacific Northwest (for the intraslab earthquakes). Recurrence intervals are based on current best estimates. Table 10-1: Seismic Sources Affecting Linn County Fault Cascadia Subduction Zone (interface earthquake) Cascadia Subduction Zone (intraslab earthquake) Maximum Magnitude Probable Recurrence Interval (years) to to 1000 Chapter 4 of the Regional Mitigation Plan Phase Two Technical Appendix analyses these two scenario earthquakes affecting the three counties: a Cascadia Subduction Zone interface earthquake (M8.5) and a Cascadia Subduction Zone intraslab earthquake (M7.5). For each of these earthquakes, appropriate attenuation relationships are used to calculate the levels of ground shaking (peak ground acceleration, PGA) with distance from the earthquake. Overall, the level of seismic hazard is relatively high for Sweet Home. Updated 2008 USGS seismic hazard maps for Oregon have increased the level of seismic hazard by about 15% visà-vis the previous 2002 maps. Figure 10-4 shows the contours of seismic ground motions in Oregon (PGA, peak ground acceleration, as a percentage of g the acceleration of gravity) City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-6

120 with a 2% chance of being exceeded in a 50-year time period. The values shown on the map are for rock sites; ground motions for soil sites will typically be higher. For Sweet Home, the 2014 USGS data are summarized in Table Table 10-2: USGS Seismic Hazard Data for Sweet Home (Approximate Values for Firm Soil Sites) Probabilistic Ground Motion PGA (% g) 10% in 50 Years 18% 2/3rds of 2% in 50 Years 24% 2% in 50 Years 36% Any of these levels of ground shaking are high enough to cause significant to substantial damage in vulnerable buildings. The 2/3rds of the 2% in 50 year ground motion is the level of ground motion required for the design of new buildings in the International Building Code. Figure 10-4: 2014 USGS Seismic Hazard Map for Oregon PGA value (%g) with a 2% Chance of Exceedance in 50 years 10.3 Earthquake Events Since 2009 There have been no significant earthquake events (that is, no damage of any sort) in or near Sweet Home since completion the 2009 update of the SHMP. However, the seismic hazard data have been updated to include the latest (2008) USGS seismic hazard data, as presented above Other Aspects of Seismic Hazards in Linn County Most of the damage in earthquakes occurs directly because of ground shaking which affects buildings and infrastructure. However, there are several other aspects of earthquakes that can result in very high levels of damage in localized sites: liquefaction, landslides, dam failures and tsunamis. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-7

121 Liquefaction Liquefaction is a process where loose, wet sediments lose strength during an earthquake and behave similarly to a liquid. Once a soil liquefies, it will tend to settle and/or spread laterally. With even very slight slopes, liquefied soils tend to move sideways downhill (lateral spreading). Settling or lateral spreading can cause major damage to buildings and to buried infrastructure such as pipes and cables. Figure 3-6 in the Regional Mitigation Plan Phase Two Technical Appendix (2001 Regional Mitigation Plan 2001) shows the areas in the three counties where liquefaction potential is high. These areas of high liquefaction potential largely follow the main river and stream drainage channels in the three county area; these are the areas with loose, wet sediments. Liquefaction does not occur in all such areas or in all earthquakes. However, in larger earthquakes with strong ground shaking and long duration shaking, liquefaction is likely in many of these high liquefaction potential areas. Settlements of a few inches or more and lateral spreads of a few inches to several feet are possible. Even a few inches of settlement or lateral spreading is likely to cause significant to major damage to affected buildings or infrastructure. For Sweet Home, a DOGAMI study of liquefaction found virtually nil potential for liquefaction in the Sweet Home area because the soils are predominantly course gravels not subject to liquefaction (DOGAMI, Relative Earthquake Hazard Maps for selected urban areas in Western Oregon (IMS-8, 1999) Landslides Earthquakes can also induce landslides, especially if an earthquake occurs during the rainy season and soils are saturated with water. The areas prone to earthquake-induced landslides are largely the same as those areas prone to landslides in general. As with all landslides, areas of steep slopes with loose rock or soils are most prone to earthquakeinduced landslides. Map 8-1 (SHMP Chapter 8) shows areas of Sweet Home subject to earthquake-induced (and other) landslides. Much of the south hills area and portions of the area north of the South Santiam River have medium risk of landslides. Much smaller localities within these general areas have been determined to have high landslide potential. To date, limited development has occurred in these high landslide potential areas although a few homes and streets/roads are located in these areas. See SHMP Chapter 8 for further discussion of landslides Dam Failures Earthquakes can also cause dam failures in several ways. The most common mode of earthquake-induced dam failure is slumping or settlement of earthfill dams where the fill has not been properly compacted. If the slumping occurs when the dam is full, then overtopping of the dam, with rapid erosion leading to dam failure is possible. Dam failure is also possible if strong ground motions heavily damage concrete dams. In a few cases, earthquake induced landslides into reservoirs have caused dam failures. Earthquake-induced dam failures are addressed in more detail in Chapter 12 which covers dam failures that could affect Sweet Home. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-8

122 Tsunamis and Seiches Tsunamis, which are often incorrectly referred to as tidal waves, result from earthquakes which cause a sudden rise or fall of part of the ocean floor. Such movements may produce tsunami waves, which have nothing to do with the ordinary ocean tides. In the open ocean, far from land, in deep water, tsunami waves may be only a few inches high and thus be virtually undetectable, except by special monitoring instruments. These waves travel across the ocean at speeds of several hundred miles per hour. When such waves reach shallow water near the coastline, they slow down and can gain great heights. Tsunamis affecting the Oregon coast can be produced from very distant earthquakes off the coast of Alaska or elsewhere in the Pacific Ocean. For such tsunamis, the warning time for the Oregon coast would be at least several hours. However, interface earthquakes on the Cascadia Subduction Zone can also produce tsunamis. For such earthquakes the warning times would be very short, only a few minutes. Because of this extremely short warning time, emergency planning and public education are essential before such an event occurs. The City of Sweet Home, not being located on the coast, cannot be directly 1 affected by such tsunamis on the Oregon Coast. Another earthquake related phenomenon is seiches which are waves from sloshing of inland bodies of waters such as lakes, reservoirs, or rivers. In some cases, seiches have caused damages to shorefront structures and to dams. However, for the Sweet Home vicinity the potential for seiches of sufficient magnitude to cause significant damage appears low Risk Assessment for Scenario Earthquakes A seismic risk assessment for Benton, Lane and Linn Counties was conducted by estimating the extent of damage and casualties likely in each of the two scenario earthquakes on the Cascadia Subduction Zone discussed above: a M8.5 interface earthquake and a M7.5 intraplate earthquake. For Level One Loss modeling, earthquake ground motions were calculated at the center of each census tract and these values were used for the entire census tract. Further technical details of the loss estimation calculations are given in Chapter 4 of the 2001 Regional Mitigation Plan, Phase Two Technical Appendix. These results were updated to 2014 values using the latest available population estimates and building values. Population estimates are from Portland State University s 2013 Annual Population Report Tables; building values were based on the Engineering News Record Building Cost Indices for For each of these scenario earthquakes, building damage estimates for Linn County are over $800,000,000. Injuries were estimated to be over 900 for daytime earthquakes and overt 200 for nighttime earthquakes. Deaths were estimated to be about 15 for daytime earthquakes and about 1 for nighttime earthquakes. Casualties are much lower for 1 Note: significant events along the Oregon coast (e.g., major Tsunamis or Cascadia Subduction zone event) could lead to numerous evacuees seeking shelter inland perhaps as far as the Sweet Home area, and/or such events could cause other disruptions throughout the state, such as power outages and transportation issues affecting normal distribution of such critical items as food and fuel supplies. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-9

123 nighttime earthquakes, because most of the population is in mostly wood-frame residential buildings, which typically have lower casualty rates than many other types of structures. Sweet Home specific results were extracted from the Linn County data, for the two census tracts within Sweet Home. Summary results are shown in Tables 10-3 and Richter Magnitude 8.5 Cascadia Subduction Zone Interface Earthquake The estimated impacts of this earthquake on the building stock in Linn County and Sweet Home are summarized below in Table Further details of the loss estimates are given in the 2001 Regional Mitigation Plan (Chapter 4 of the Phase Two Technical Appendix). In addition to building damages, utility systems are also likely to experience significant damage. The Phase Two Regional Mitigation Plan had generalized comments about the expected levels of damages. However, for an area as small as Sweet Home, estimating the specific levels of utility damages and outages would require site-specific analyses. Table 10-3: M8.5 Cascadia Subduction Zone Interface Earthquake Loss Estimate Linn County Sweet Home Building Damage $870,000,000 $91,000,000 Percent Damage % 10.18% Daytime Deaths Daytime Injuries Nighttime Deaths Nighttime Injuries Heavily Damaged Residential Buildings Estimated Number of People Needed Emergency Shelter Percent damage is relative to building replacement value. 2 Fractional deaths are statistical results. For example, 0.1 death means about a 10% chance of one death. 3 Heavily damaged buildings are those in the extensive or complete damage states, as defined by FEMA's HAZUS loss estimation method.. 4 Of the total displaced people, approximately 1/3rd may need public emergency shelter with the rest finding shelter with relatives, friends or in commercial lodging. The direct loss estimates shown above are for the building stock only. Including the direct damages to contents, infrastructure and direct economic impacts from loss of function, the total direct economic impacts of these scenario earthquakes may be about double the estimates shown above. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-10

124 Richter Magnitude 7.5 Cascadia Subduction Zone Intraplate Earthquake The estimated impacts of this earthquake on the building stock in Linn County and Sweet Home are summarized below in Table Table 10-4: M7.5 Cascadia Subduction Zone Intraplate Earthquake Loss Estimate Linn County Sweet Home Building Damage $810,000,000 $81,000,000 Percent Damage % 10.18% Daytime Deaths Daytime Injuries Nighttime Deaths Nighttime Injuries Heavily Damaged Residential Buildings Estimated Number of People Needed Emergency Shelter Percent damage is relative to building replacement value. 2 Fractional deaths are statistical results. For example, 0.1 death means about a 10% chance of one death. 3 Heavily damaged buildings are those in the extensive or complete damage states, as defined by FEMA's HAZUS loss estimation method.. 4 Of the total displaced people, approximately 1/3rd may need public emergency shelter with the rest finding shelter with relatives, friends or in commercial lodging. The direct loss estimates shown above are for the building stock only. Including the direct damages to contents, infrastructure and direct economic impacts from loss of function, the total direct economic impacts of these scenario earthquakes may be about double the estimates shown above. In addition to building damages, utility systems are also likely to experience significant damage. The Phase Two Regional Mitigation Plan had generalized comments about the expected levels of damages. However, for an area as small as Sweet Home, estimating the specific levels of utility damages and outages would require site-specific analyses. The probable impacts of major earthquakes on Sweet Home are summarized below in Table In addition to the probable impacts summarized in the table, there is an extremely low probability that a major earthquake could result in substantial damage or failure of the major dams upstream of Sweet Home. If dam failure were to occur, however, the impact on Sweet Home could be very large with very high damage levels in inundation areas and potentially high casualties (depending on the extent of dam damage, the amount of warning time of dam failure, and the effectiveness of evacuations). City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-11

125 Table 10-5: Probable Impacts of Major Earthquakes on Sweet Home Inventory Portion of Sweet Home affected Buildings Streets within Sweet Home Roads to/from Sweet Home Electric power Other Utilities Casualties Probable Impacts Entire City and surrounding region Most buildings will have no damage or light to moderate damage, with heavy damage concentrated in vulnerable buildings (wood frame buildings with cripple walls, unreinforced masonry, etc.). Total building damage estimated to be about $50,000,000. Minor damage possible in areas of soft soils. Minor damage possible in areas of soft soils. Short outage of electric power is likely, with duration ranging from a few hours to 1 day. Generally minor damage to water, wastewater and natural gas systems, including a few pipe breaks. Possible damage to water and wastewater treatment plants. Small potential for deaths (statistical estimate is about 1 death for daytime earthquake and about 0.1 for nighttime earthquake) and a couple dozen injuries (nighttime) or several dozen injuries (daytime). The above summary of potential impacts is for major earthquakes on the Cascadia Subduction Zone, as shown in the Tables above. Smaller earthquakes would have generally substantially smaller impacts than shown above Earthquake Risk Assessment: Technical Guidance Level Two Risk Assessment The Level One earthquake loss estimates presented above are based on census-tract level data. For a given community, such as Sweet Home, a more accurate loss estimate could be obtained by incorporating Level Two local data into the loss calculations. Such data could include: 1) better inventory data, 2) spatial distribution of inventory within census tracts, 3) overlay of soils information with inventory to identify areas subject to amplification, liquefaction, settling and displacements, and 4) refinement of building fragility curves to reflect local inventory. Such Level Two loss estimates would be more accurate than the Level One assessments presented above. However, the Level One estimates probably provide accurate enough estimates of the approximate magnitude of losses for emergency planning purposes. Furthermore, conducting a Level Two loss estimate would require very intensive data collection and processing efforts, without providing enough detail for specific mitigation projects. Therefore, Level Two risk assessments may not be as useful for Sweet Home as the Level Three Assessments suggested below. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-12

126 Level Three Risk Assessment The potential damages and losses from earthquakes affecting Linn County and Sweet Home are very high. However, the probability of such earthquakes is relatively low. Therefore, widespread mitigation of seismic hazards is probably not called for in the case of most ordinary or typical buildings. New buildings will be built in accordance with current building code requirements and thus the seismic capacity of the building stock will improve over time as the existing stock is gradually replaced and/or upgraded. However, for some types of buildings, which are more vulnerable or more important than typical buildings, seismic retrofit may be highly desirable. Prime candidates for possible seismic retrofits include: any buildings that are substantially more vulnerable than typical buildings (e.g., unreinforced masonry buildings), buildings on soft soil sites, and essential service facilities such as major medical facilities, police and fire stations, schools, and emergency shelters. Specific buildings may be substantially more vulnerable than typical buildings because of their structural system. Examples of vulnerable building types include: unreinforced masonry, precast concrete frame, concrete or steel frame with unreinforced masonry infill walls, concrete moment resisting frame, and precast concrete tiltup walls. Buildings may also be substantially more vulnerable than typical buildings because of their design characteristics. Examples include buildings with soft first stories (taller than other stories and/or with large expanses of windows without shear walls) and buildings with major configurational irregularities, as well as wood frame buildings with cripple wall foundations or with sill plates not bolted to the foundation. Thus, we suggest that Level Three risk assessments focus primarily on such buildings, especially for essential service facilities. A Level Three assessment provides a building-specific evaluation, more accurate than generic assessments based on typical buildings. Ideally, a Level Three assessment would include a site specific seismic hazard analysis, taking into account soil conditions, and a buildingspecific evaluation of the seismic vulnerability of each building under evaluation. For such buildings, the seven-step Mitigation Planning methodology outlined in Chapter 1 is appropriate. For prioritizing between mitigation projects, the principles of benefit-cost analysis apply to mitigation projects for all hazards, including seismic hazard mitigation. FEMA has software available to conduct such analyses of prospective earthquake hazard mitigation projects. See also the example seismic mitigation project in the Appendix Seismic Windshield Survey for Sweet Home A windshield survey means a quick, preliminary seismic risk evaluation of a building or other facility, based on readily observable external attributes. A windshield survey may literally be done from a vehicle, but more commonly includes a quick walk around inspection. Conclusions drawn from such preliminary evaluations must be interpreted carefully as giving only a general indication of the probable level of seismic risk posed by the building or facility. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-13

127 Overall, the building inventory in Sweet Home is primarily residential, with most residential structures being wood frame buildings. In general, wood frame buildings perform well in earthquakes, with a few notable exceptions. Wood frame buildings with the following characteristics are generally substantially vulnerable to major seismic damage: 1) sill plates not bolted to foundation, 2) cripple wall perimeter systems, and 3) buildings on steep slopes, partially supported on stilts. Cripple wall perimeter systems are short wooden walls which raise the first floor elevation above grade by typically about 2 to 4 feet. Unbolted sill plates and cripple wall construction are common in pre-ww2 construction. Visual inspection and the general vintage of building stock in Sweet Home suggest that there are likely significant numbers of buildings in Sweet Home with cripple wall foundations or with unbolted sill plates. Unreinforced masonry buildings are also subject to major damage in earthquakes. Sweet Home has a couple dozen masonry buildings (most commercial or industrial) which may be unreinforced or reinforced masonry. A detailed inventory of wood frame buildings with the above noted seismic deficiencies and inventory of unreinforced masonry buildings would be useful to further quantify the level of risk posed by such structures in Sweet Home. Most City-owned facilities in Sweet Home were inspected to draw preliminary inferences about the level of seismic risk posed by the facility. The complete list is given in Section 3 of the Technical Appendix. Facilities were ranked on a four point scale including very low (VL), low (L), low-medium (L-M), and medium (M). This classification was based on estimated seismic performance for ground shaking at 0.3 g (the current seismic design level for Seismic Zone 3 in Western Oregon). This level of ground shaking (0.3 g) is slightly higher than the most likely levels of ground shaking in Sweet Home from major earthquakes on the Cascadia Subduction Zone, but appropriate for mitigation planning purposes. Important conclusions from this very preliminary evaluation were that the water treatment plant had numerous seismic deficiencies and that the wastewater treatment plant has some seismic deficiencies. The City constructed a new water treatment plant in 2009 which is built to meet the International Building Code standards for earthquakes. Further engineering study is also recommended for the Weddle Bridge, which may be subject to failure from lateral spreading of soils underlying the footings in earthquakes. High priority items for non-structural mitigation projects (bracing, anchoring of contents) include possible failure of communications equipment which could significantly impact the efficiency of police response capabilities during an earthquake event Earthquake Hazard Mitigation Projects There are a wide variety of possible hazard mitigation projects for earthquakes. The most common projects include: structural retrofit of buildings, non-structural bracing and anchoring of equipment and contents, and strengthening of bridges and other infrastructure components. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-14

128 The seismic hazard (frequency and severity of earthquakes) is moderately high in Sweet Home. However, the risk (potential for damages and casualties) may be fairly high because some buildings and infrastructure may be highly vulnerable to earthquake damages. The risk assessment methodology outlined above for earthquakes provides the basis for identifying the high risk facilities that then become the primary targets for mitigation. Structural retrofit of buildings should not focus on typical buildings, but rather on buildings that are most vulnerable to seismic damage. Priorities should include buildings on soft soil sites subject to amplification of ground motion and/or liquefaction and especially on critical service facilities such as hospitals, fire and police stations, emergency shelters, and schools. Non-structural bracing of equipment and contents is often the most cost-effective type of seismic mitigation project. Inexpensive bracing and anchoring may protect very expensive equipment and/or equipment whose function is critical such as medical diagnostic equipment in hospitals, computers, and communication equipment for police and fire services and so on. For utilities, bracing of control equipment, pumps, generators, battery racks and other critical components can be powerfully effective in reducing the impact of earthquakes on system performance. Such measures should almost always be undertaken before considering large-scale structural mitigation projects. The strategy for strengthening bridges and other infrastructure follows the same principles as discussed above for buildings. The targets for mitigation should not be typical infrastructure but rather specific infrastructure elements that have been identified as being unusually vulnerable and/or are critical links in the lifeline system. For example, vulnerable overpasses on major highways would have a much higher priority than overpasses on lightly traveled rural routes. To demonstrate this type of detailed, facility-specific analysis, a prospective seismic retrofit for a fire station in Albany is given as an example in the Appendix from the 2001 Regional Mitigation Plan, Phase Two. Table 10-6 contains earthquake mitigation action items from the master Action Items in Chapter 4. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-15

129 OG 10 Yrs OG OG OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built -Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Earthquake Mitigation Action Items Table 10-6: Earthquake Mitigation Action Items Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 ST #1 Obtain and make available to the public FEMA pamphlets to educate building owners and residents about structural and non-structural retrofitting of vulnerable homes and encourage retrofits. SHMPC City X X X LT #1 (1a) Complete inventory of important buildings, including schools, that may be particularly vulnerable to earthquake damage using FEMA s Rapid Visual Screening, (1b) and, as needed and as funding is available, conduct more detailed seismic vulnerability analysis of buildings which appear particularly vulnerable [*may require technical assistance from consultants]. CCDD; SH School District City, SH School District, FEMA X LT #2 Complete inventory of residential and commercial buildings that may be particularly vulnerable to earthquake damage, including pre-1940s homes, unreinforced masonry buildings, tilt-up buildings and buildings with soft first stories. [*May require technical assistance from consultants, and additional funding.] CCDD City, FEMA X LT #3 Seek funding to retrofit important public facilities with significant seismic vulnerabilities. CCDD City, FEMA X X X X X LT #4 Same as ST#4 in Table 4-2, and ST#1 and LT#3 in Table 4-4. (Addresses Critical Facilities and Emergency Shelters.) Same City X X X X Same as Table 4-7 in Chapter 4, page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 10-16

130 11.1 Overview 11.0 Volcanic Hazards The Cascades, which run from British Columbia through Washington and Oregon into northern California, contain more than a dozen major volcanoes and hundreds of smaller volcanic features. In the past 200 years, seven of the Cascade volcanoes in the United States have erupted, including: Mt. Baker, Glacier Peak, Mt. Ranier, Mount St. Helens, Mt. Hood, Mt. Shasta, and Mt. Lassen. Over the past 4000 years (a geologically very short time period) in Oregon there have been three eruptions of Mt. Hood, four eruptions in the Three Sisters area, and two eruptions in the Newberry Volcano area and minor eruptions near Mt. Jefferson, at Blue Lake Crater, in the Sand Mountain Field (Santiam Pass), near Mt. Washington, and near Belknap Crater. During this time period, the most active volcano in the Cascades has been Mount St. Helens with about 14 eruptions. In addition, many other volcanoes in Oregon are deemed active or potential active. The Smithsonian Institutions Global Volcanism Project lists 20 active volcanoes in Oregon. These volcanoes are listed below in Table Table 11-1: Active Volcanoes in Oregon Volcano Type Last Eruption Mt. Hood Stratovolcano 1866 Mt. Jefferson Stratovolcano 950 main volcano inactive for >10,000 years Blue Lake Crater Crater 1490 BC Sand Mountain Field Cinder cones 1040 BC? Mt. Washington Shield volcano 620 main volcano inactive Belknap Field Shield volcanoes 460? North Sister Field Complex volcano 350 South Sister Complex volcano 50 BC? Mt. Bachelor Stratovolcano 5800 BC Davis Lake Volcanic field 2790 BC? Newberry Volcano Shield volcano 620 crater formation 300,000 to 500,000 years ago Devis Garden Volcanic field unknown Squaw Ridge Lava Field Volcanic field unknown Four Craters Lava Field Volcanic field unknown Cinnamon Butte Cinder cones unknown Crater Lake Caldera 2290 BC Crater formation about 7,700 years ago Diamond Craters Volcanic field unknown Saddle Butte Volcanic field unknown Jordan Craters Volcanic field 1250 BC Jackies Butte Volcanic field unknown City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 11-1

131 On a longer geological time scale, volcanic activity in the Cascades has been very widespread. A DOGAMI report on prehistoric and historic volcanic eruptions in Oregon (see website below) notes that in the Cascades as a whole, over 3000 large and small volcanoes have erupted over the past five million years. Within historical times, between 1843 and 1860 there were a series of 21 eruptions in the Cascades and there is some scientific speculation that the Northwest may be entering another period of volcanic activity. A great deal of general background information on Oregon volcanoes and on volcanoes in general is available on several websites, including the following in Table Table 11-2: Volcano Websites Institution Smithsonian Institution (Global Volcanism Project) United States Geological Survey (USGS) - general site USGS Cascades Volcano Observatory (Vancouver, WA) DOGAMI Website The numerous volcanoes of the Cascades differ markedly in their geological characteristics. The largest volcanoes are generally what geologists call composite or stratovolcanoes. These volcanoes may be active for tens of thousands of years to hundreds of thousands of years. In some cases, these large volcanoes may have explosive eruptions such as Mt. St. Helens in 1980 or Crater Lake about 7,700 years ago. The much more numerous sites of volcanic activity are generally what geologists call mafic volcanoes. This type of volcano is typically active for much shorter time periods, up to a few hundred years, and generally forms small craters or cones. Mafic volcanoes are not subject to large explosive events Volcanic Hazard Types In Oregon, awareness of the potential for volcanic eruptions was greatly increased by the May 18, 1980 eruption of nearby Mount St. Helens in Washington which killed 57 people. In this eruption, lateral blast effects covered 230 square miles and reached 17 miles northwest of the crater, pyroclastic flows covered six square miles and reached 5 miles north of the crater, and landslides covered 23 square miles. Ash accumulations were about 10 inches at 10 miles downwind, 1 inch at 60 miles downwind, and ½ inch at 300 miles downwind. Lahars (mudflows) affected the North and South Forks of the Toutle River, the Green River, and ultimately the Columbia River as far as 70 miles from the volcano. Volcanic eruptions often involve several distinct types of hazards to people and property, as well evidenced by the Mount St. Helens eruption. Major volcanic hazards include: lava flows, blast effects, pyroclastic flows, ash flows, lahars, and landslides or debris flows. Some of these hazards (e.g., lava flows) only affect areas very near the volcano. Other hazards may affect areas 10 or 20 miles away from the volcano, while ash falls may affect areas many miles downwind of the eruption site. These six volcanic hazards are summarized below. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 11-2

132 1) Lava flows are eruptions of molten rock. Lava flows for the major Cascades volcanoes tend to be thick and viscous, forming cones and thus typically affecting areas only very near the eruption vent. However, flows from the smaller mafic volcanoes may be less viscous flows that spread out over wider areas. Lava flows obviously destroy everything in their path. 2) Blast effects may occur with violent eruptions, such as Mount St. Helens in Most volcanic blasts are largely upwards. However, the Mount St. Helens blast was lateral, with impacts 17 miles from the volcano. Similar or larger blast zones are possible in future eruptions of any of the major Cascades volcanoes. 3) Pyroclastic flows are high-speed avalanches of hot ash, rock fragments and gases. Pyroclastic flows can be as hot as 1500 o F and move downslope at 100 to 150 miles per hour. Pyroclastic flows are deadly for anyone caught in their path. 4) Ash falls result when explosive eruptions blast rock fragments into the air. Such blasts may include tephra (solid and molten rock fragments). The largest rock fragments (sometimes called bombs ) generally fall within two miles of the eruption vent. Smaller ash fragments (less than about 0.1 ) typically rise into the area forming a huge eruption column. In very large eruptions, ash falls may total many feet in depth near the vent and extend for hundreds or even thousands of miles downwind. 5) Lahars or mudflows are common during eruptions of volcanoes with heavy loading of ice and snow. These flows of mud, rock and water can rush down channels at 20 to 40 miles an hour and can extend for more than 50 miles. For some volcanoes, lahars are a major hazard because highly populated areas are built on lahar flows from previous eruptions. 6) Landslides or debris flows are the rapid downslope movement of rocky material, snow and/or ice. Volcano landslides can range from small movements of loose debris to massive collapses of the entire summit or sides of a volcano. Landslides on volcanic slopes may be triggered be eruptions or by earthquakes or simply by heavy rainfall Volcanic Hazards for Linn County and Sweet Home Several of the 20 active volcanoes in Oregon are located along the crest of the Cascades near the eastern boundary of Linn County (see Table 11-1 above). These volcanoes include: Mt. Jefferson, Blue Lake Crater, Mt. Washington, the Belknap Crater Field, and the Sand Mountain Field. In addition, other active volcanoes are near enough to Linn County to impact the County, including the Three Sisters. Among the Linn County volcanoes, Mt. Jefferson and Mt. Washington have not been active for perhaps 15,000 years for Mt. Jefferson and for several hundred thousand years for Mt. Washington. Mt. Jefferson is potentially active, while Mt. Washington is probably extinct. Most of the other Linn County volcanoes are smaller mafic volcanoes or volcanic fields (clusters of cones, vents, craters) that typically have smaller, much more localized eruptions compared to the larger volcanoes. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 11-3

133 Sweet Home is about 40 miles (as the crow flies) from the nearest active volcano (the Sand Mountain Field near the Santiam Pass), and approximately 50 miles from the nearest large volcanoes (Mt. Jefferson and North Sister). These distances are large enough that Sweet Home is extremely unlikely to have major impacts from eruptions of any of these volcanoes. However, for completeness, we review the volcanic hazards posed by the Three Sisters, which are the nearest, most recently active major volcanoes near Sweet Home. Awareness of potential volcanic activity at the Three Sisters has been raised because of the recent discovery of an uplift (bulge) on the west side of South Sister In May 2001, the USGS announced that it had detected a slight swelling or uplift of the west side of South Sister. This bulge, which occurred between 1996 and 2000, covers an area about 9 to 12 miles in diameter, with a maximum bulge in the center of about 4 inches. The cause of this uplift (bulge) is most likely intrusion of a small amount of magma (molten rock) deep under the surface, probably at a depth of about 4 miles. This observation confirms that South Sister is still an active volcano, but needs to be interpreted cautiously. For comparison, a bulge was also observed on the north side of Mount St. Helens in the months prior to the May 18, 1980 eruption. However, the Mount St. Helens bulge was 450 feet high and growing at a rate of 5 feet per day prior to the eruption. Thus, the South Sister bulge of 4 inches is certainly not an indication of an imminent eruption. The UGSG analysis of Volcano Hazards in the Three Sisters Region, Oregon was published in 1999 (Open-File Report ). The Three Sisters area includes two large composite volcanoes (Middle and South Sister). Large composite volcanoes in the Cascades (e.g., Mt. Hood, Mt. Jefferson, Newberry Volcano, and Crater Lake) are often active for hundreds of thousands of years and are subject to sometimes explosive eruptions (e.g., Mount St. Helens in 1980). Hazards from eruptions of composite volcanoes include all of the hazards listed above in Section Between the major composite volcanoes, the crest of the Cascades is built up of hundreds of mafic volcanoes. Mafic volcanoes typically erupt for a few weeks to a few centuries, although some can be nearly as large as the composite volcanoes. Prominent mafic volcanoes in the Three Sisters area include North Sister, Mount Bachelor, Belknap Cater, Black Butte, and Mount Washington. Mafic volcanoes often form broad fields of volcanic vents such as in the Sand Mountain Field near the Santiam Pass, north of the Three Sisters. Mafic volcanoes typically erupt less explosively than do composite volcanoes, so that impacts of eruptions are less widespread. Most mafic eruptions in the Three Sisters areas have produced tephra deposits and lava flows that typically traveled 3 to 9 miles from the vents and rarely 9 to 12 miles from the vents. Tephra deposits rarely exceed 4 inches in thickness at distances 6 miles from the vent. Belknap Crater, about 1,500 years old, is one of the youngest mafic volcanoes in the Cascades. The Sand Mountain Field, a cluster of cones and lava flows west of Santiam Pass, was formed during three eruptive periods between about 2,000 and 4,000 years ago. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 11-4

134 The USGS study of Volcano Hazards in the Three Sisters Region includes three hazard zones: proximal hazards, distal hazards, and a regional lava flow hazard zone. These three hazard zones are summarized below. 1) The proximal hazard zone is limited to the immediate area around the Three Sisters and is an oval area about 8 miles (east-west) by 10 miles (north-south). The proximal hazard area is the area subject to the most intense volcanic hazards including lava flows, tephra flows, pyroclastic flows, landslides and debris flows and lahars. Fortunately, this area is predominantly wilderness with very low population. 2) The distal hazard zones are river valleys extending away from the proximal hazard zone that are subject to landslides, debris flows and lahars. The distal hazard zone has three levels for areas subjected to lahars (and other flows) of varying sizes. Areas subjected to lahars include Squaw Creek into Sisters, Tumalo Creek into Bend, the valley between Sparks Lake and Crane Prairie Reservoir, and the McKenzie River (and tributaries) west of the Three Sisters. 3) The regional lava flow hazard zone includes a band about 30 to 40 miles wide covering the entire crest of the Cascades. Locations throughout this zone, which includes Sisters, Bend, and the Santiam Pass, are subject to lava flows from mafic volcanism would could occur anywhere in this entire zone. None of these Three Sisters volcanic hazards zones impact Sweet Home. Thus, the extent of volcanic hazards for Sweet Home appears limited to the possibility of minor ash falls from eruptions at Three Sisters, at other locations in the Cascades or elsewhere (e.g., Mount St. Helens). In all but the most extreme events, ash falls in Sweet Home are likely to be minor with an inch or less of ash likely. Volcanic events in the Three Sisters area or in the Santiam Pass area (Sand Mountain volcanic field) could also close eastbound Highway 20 and thus affect transportation to/from Sweet Home. The probable impacts of potential volcanic eruptions on the City of Sweet Home are summarized below in Table Table 11-3: Probable Impacts of Potential Volcanic Eruptions on the City of Sweet Home Inventory Portion of Sweet Home affected Buildings Streets within Sweet Home Roads to/from Sweet Home Electric power Other Utilities Casualties Probable Impacts Entire City and surrounding region Negligible impact, other than minor cleanup required Negligible impact, other than minor cleanup required Negligible impact, other than minor cleanup required Power outages likely from short circuits caused by ash falls Negligible impact, other than minor cleanup required for most utilities. Potential to impact water treatment plants which may require additional maintenance to deal with high turbidity water Some potential for health impacts, especially for frail people with respiratory problems Volcanic Events Since the 2009 Update of the SHMP There have been no volcanic events affecting Sweet Home since completion of the 2009 update of Sweet Home Mitigation Plan. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 11-5

135 11.5 Mitigation of Volcanic Hazards Mitigation of volcanic hazards is predominantly in the areas of monitoring volcanic activity, warnings and evacuation, and emergency response. That is, there are few, if any, practical physical measures to mitigate the direct impacts of volcanic activity. The USGS actively monitors volcanic activity in the Cascades via networks of seismic sensors (which can detect earthquakes related to magma movements) as well as very accurate ground surface measurements, such as that which has detected the very small bulge on South Sister. The USGS also has a volcanic warning system with several levels of alert as a potential eruption becomes more likely and more imminent. For the Cascades, the USGS volcano warning system ( has three levels. Level One (Volcanic Unrest) means anomalous conditions that could be indicative of an eventual volcanic eruption. Level Two (Volcanic Advisory) means that processes are underway that have a significant likelihood of culminating in hazardous volcanic activity, but when the evidence does not indicate that a life- or property-threatening event is imminent. Level Three (Volcano Alert) means that monitoring or evaluation indicate that precursory events have escalated to the point where a volcanic event with attendant volcanologic or hydrologic hazards threatening to life and property appears imminent or is underway. For Sweet Home, which is located well outside of any of the likely direct hazard zones for any Cascades volcanic events, mitigation for volcanic activity is likely a low priority. In the event of a minor ash flow, public warnings directing people (especially those with respiratory problems) to remain indoors, and minor cleanup are most likely the only necessary responses for Sweet Home. Table 11-4 includes the volcanic hazards mitigation action items from the master Action Items in Chapter 4. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 11-6

136 1-2 Yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 11-4 Volcanic Hazards Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Volcanic Hazards Mitigation Action Items ST #1 Evaluate capability of the new water treatment plant to deal with high turbidity from ash falls and upgrade emergency response plan to deal with ash falls. CPWD City X X Same as Table 4-8 in Chapter 4, page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 11-7

137 12.1 Overview 12.0 Dam Failures Dams are manmade structures built to impound water. Dams are built for many purposes including water storage for potable water supply, livestock water supply, irrigation, or fire suppression. Other dams are built for flood control, recreation, flood control, navigation, and hydroelectric power or to contain mine tailings. Dams may also be multifunction, serving two or more of these purposes. Dams are manmade structures built to impound water. Dams are built for a wide range of purposes including water storage for potable water supply, livestock water supply, irrigation, or fire suppression. Other dams are built for flood control, recreation, flood control, navigation, and hydroelectric power or to contain mine tailings. Dams may also be multifunction, serving two or more of these purposes. The National Inventory of Dams, NID, which is maintained by the United States Army Corps of Engineers, is a database of approximately 76,000 dams in the United States. The NID does not include all dams in the United States. Rather, the NID includes dams that are deemed to have a high or significant hazard potential and dams deemed to pose a low hazard if they meet inclusion criteria based on dam height and storage volume. Low hazard potential dams are included if they meet either of the following selection criteria: 1) exceeds 25 feet in height and 15 acre-feet of storage, or 2) exceeds 6 feet in height and 50-acre feet of storage. There are many thousands of dams too small to meet the NID selection criteria. However, these small dams are generally too small to have significant impacts if they fail and thus are generally not considered for purposes of risk assessment or mitigation planning. This NID potential hazard classification is solely a measure of the probable impacts if a dam fails. Thus, a dam classified as High Potential Hazard does not mean that the dam is unsafe or likely to fail. The level of risk (probability of failure) of a given dam is not even considered in this classification scheme. Rather, the High Potential Hazard classification simply means that there are people at risk downstream from the dam in the inundation area, if the dam were to fail. The NID potential hazard classification system for dams is as summarized below in Table Hazard Potential Classification Table 12-1: NID Hazard Potential Classification for Dams 1 Loss of Human Life Economic, Environmental, or Lifeline Losses Low None expected Low and generally limited to dam owner Significant None expected Yes High Probable, one or more expected Yes, but not necessary for this classification. Dams assigned the low hazard potential classification are those where failure or misoperation results in no probable loss of human life and low economic and/or environmental losses. Such losses are principally limited to the dam owner s property. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-1

138 Dams assigned to the significant hazard potential classification are those where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, or disruption of lifeline facilities. Significant hazard potential dams are often located in predominantly rural or agricultural areas. Dams assigned to the high hazard potential classification are those where failure or misoperation will probably cause loss of human life. Failure of dams in the high classification will generally also result in economic, environmental or lifeline losses, but the classification is based solely on probable loss of life. Of the dams in the NID, nearly 60% are privately owned. In addition to the dams in the NID, there are many thousands of dams too small to meet the selection criteria for the NID. Most of these small dams are also privately owned. The NID is available online through several links at FEMA and the United States Army Corps of Engineers. However, since September 11, 2001, basic NID information and links to the database at is access restricted Dam Primer In the simplest terms, dams are impervious structures that block the flow of water in a river or stream and thereby impound water behind the dam. Dams have been built for thousands of years from a wide range of materials, including earth, stone, masonry, wood, and concrete. Large modern dams are almost always embankment dams (built primarily from soil, rock, or mixtures) or concrete dams. Large modern dams almost always have control mechanisms such as gated spillways or outlet pipes for releasing water in a controlled fashion. Typically, dams are operated to smooth natural variations in water flow. During high water flow periods, water is stored behind a dam, while in low water flow periods, water is released to increase flows. Controlled releases typically result in lower peak (flood) flows and higher minimum flows than in uncontrolled streams. The specific patterns of water storage and release vary from dam to dam, depending on the primary purpose(s) of the dam and on a wide variety of economic, regulatory and environmental considerations Dam Nomenclature and Types of Dams Modern dams, whether embankment dams or concrete dams, are typically constructed on a foundation, which may be concrete, natural rock or soils, or compacted soils. Dams are usually constructed along a constricted part of a river valley to minimize cost. Dams are also connected to the surrounding natural valley walls, which become the abutments of the dam structure itself. Embankment dams are commonly termed earthfill or rockfill dams, depending on the primary material used in their construction. Historically, a wide range of earth and rock materials have been used to construct embankment dams, with various construction techniques including hydraulic fill and compaction. Embankment dams are broad flat structures, typically at least twice as wide at the base as their height. In cross section, embankment dams are typically trapezoidal, with a wide flat base, sloping slides and a narrower flat top. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-2

139 Depending on the permeability of the materials used in an embankment dam, impervious layers may be added to the upstream side of the structure or in the center core of the structure. Embankment dams are subject to erosion by running water. Thus, modern embankment dams always have erosion-resistant materials used in the water release and control mechanisms of the dam. Typically, concrete spillways with concrete or steel gates are used to control releases. Many dams also have outlet pipe systems with concrete or steel pipes as part of the water release control system. Modern concrete dams fall into two major classes: gravity dams and arch dams. Concrete gravity dams are designed on principles similar to embankment dams. Concrete gravity dams are broad structures, generally triangular in shape with a flat base, a narrow top, a flat upstream side and a broad sloping downstream side. Much of these dams capacity to impound water arises from the weight of the dam. Typically, gravity dams are keyed into bedrock foundations and abutments to increase the stability of the dam. Concrete arch dams rely primarily on the strength of concrete to impound water. Concrete arch dams are much thinner in cross section than concrete gravity dams. Concrete arch dams are always convex on the upstream side and concave on the downstream side because concrete is much stronger in compression than in tension. With this arch design, the pressure of impounded water compresses the concrete and makes the dam stronger. Like concrete gravity dams, concrete arch dams are also keyed into bedrock foundations and abutments to provide stability. A less common variation of a concrete arch dam is a concrete buttress dam. Buttress dams are arched or straight dams with additional strength provided by buttresses perpendicular to the long axis of the dam. An excellent introduction to dam nomenclature and descriptions of types of dams is given in the FEMA publication: Dam Safety: An Owner s Guidance Manual. 3 For further details, the reader is referred to this publication and the references therein Dam Failure Modes Dam failures can occur at any time in a dam s life; however, failures are most common when water storage for the dam is at or near design capacity. At high water levels, the water force on the dam is higher and several of the most common failure modes are more likely to occur. Correspondingly, for any dam, the probability of failure is much lower when water levels are substantially below the design capacity for the reservoir. For embankment dams, the most common failure mode is erosion of the dam during prolonged periods of rainfall and flooding. When dams are full and water inflow rates exceed the capacity of the controlled release mechanisms (spillways and outlet pipes), overtopping may occur. When overtopping occurs, scour and erosion of either the dam itself and/or of the abutments may lead to partial or complete failure of the dam. Especially for embankment dams, internal erosion, piping or seepage through the dam, foundation, or abutments can also lead to failure. For smaller dams, erosion and weakening of dam structures by growth of vegetation and burrowing animals is a common cause of failure. For embankment dams, earthquake ground motions may cause dams to settle or spread laterally. Such settlement does not generally lead, by itself, to immediate failure. However, if the dam is full, relatively minor amounts of settling may cause overtopping to occur, with resulting scour and erosion that may progress to failure. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-3

140 For any dam, improper design or construction or inadequate preparation of foundations and abutments can also cause failures. Improper operation of a dam, such as failure to open gates or valves during high flow periods can also trigger dam failure. For any dam, unusual hydrodynamic (water) forces can also initiate failure. Landslides into the reservoir, which may occur on their own or be triggered by earthquakes, may lead to surge waves which overtop dams or hydrodynamic forces which cause dams to fail under the unexpected load. Earthquakes can also cause seiches (waves) in reservoirs that may overtop or overload dam structures. In rare cases, high winds may also cause waves that overtop or overload dam structures. Concrete dams are also subject to failure due to seepage of water through foundations or abutments. Dams of any construction type are also subject to deliberate damage via sabotage or terrorism. For waterways with a series of dams, downstream dams are also subject to failure induced by the failure of an upstream dam. If an upstream dam fails, then downstream dams also fail due to overtopping or due to hydrodynamic forces. An excellent review of the common mechanisms for dam failures is given in the FEMA publication: Dam Safety: An Owner s Guidance Manual. 3 For further details, the reader is referred to this publication and the references therein. A National Research Council study 4 of dam failures in the United States and Western Europe from 1900 to 1969 compiled historical data on the observed probability of failure as a function of type of dam. Dam failures are quite common in the United States. For example, FEMA data from Tropical Storm Alberto (1994) show 230 dam failures in the State of Georgia from this single event. 5 Fortunately, most dam failures are of small dams where the failure poses little or no risk to life safety and only minor, localized property damage. Most failures are of dams that are too small to be included in the NID database or dams in the NID Low Hazard Potential Category. However, in the United States between 1960 and 1997 there were 23 dam failures that caused at least one death, with total fatalities from these 23 failures estimated at 318 people. 5 Since 1874, there have been six dam failures in the United States which killed over 100 people. 2 The worst dam failure, in terms of casualties, was the 1889 Johnstown Pennsylvania dam failure which killed over 2,200 people. Three of the high fatality dam failures occurred in the 1970s: Black Hills, South Dakota, Big Thompson River, Colorado, and Buffalo Creek, West Virginia. These three failures alone resulted in an estimated 514 deaths. 2 (Note: the published death statistics in this paragraph from these two FEMA sources are inconsistent, but these differences are not significant for the present purposes) Oregon Dam Data The National Inventory of Dams (NID) lists 964 dams in Oregon. Of these NID dams, 27 are in Linn County. The statistical breakdown of these dams by NID Potential Hazard Categories is shown below in Table City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-4

141 Table 12-2: Numbers of Dams by NID Potential Hazard Categories NID Hazard Oregon Linn County High Significant Low Undetermined 0 0 Total For Oregon, there are 154 dams in the High Potential Hazard Category. In Linn County, there are 7 dams in the High Potential Hazard Category. These 7 dams are listed individually in Table 12-3 below. Table 12-3: NID High Potential Hazard Dams in Linn County Dam Name River City NID Height (feet) NID Storage (acre feet) Foster South Santiam Sweet Home ,000 Willamette National Log Pond South Santiam Foster Big Cliff North Santiam Mill City 141 5,930 Detroit North Santiam Mill City ,000 Green Peter Middle Santiam Sweet Home ,000 Trail Bridge Mckenzie & Smith Rivers Eugene 96 2,263 Smith River Mckenzie & Smith Rivers Eugene ,000 Source: Oregon Water Resource Department Of these NID dams, the Willamette National Log Pond no longer exists. The only two dams which can affect Sweet Home are the Foster and Green Peter Dams which are located upstream of Sweet Home Dam Failure Hazard Assessment: Sweet Home A 1987 report on Dam/Levee Failure by the Oregon Emergency Management Division lists 51 historical dam failures in Oregon from 1896 through the 1980s.⁶ As of the time of this report, no dam failure fatalities had been recorded in Oregon. However, the potential for dam failure fatalities certainly exists in Oregon, in Linn County and in Sweet Home, albeit with a low probability of occurrence. To evaluate the level of risk posed by the dams affecting Sweet Home, we consider primarily the two dams in the NID high potential hazard classification (Foster and Green Peter) where the potential impacts of failure, including life safety, are greatest. Much smaller dams in the significant and low potential hazard categories do not pose a life safety threat and the risk of property damage is minimal or low. Additional data on Foster and Green Peter dams is given below in Table City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-5

142 Table 12-4: Additional Data on NID High Hazard Potential Dams County Dam Name River Storage (acre feet) Date Built Dam Type EAP Owner Linn Foster South Santiam 61, ER Y Corps Linn Green Peter Middle Santiam 430, PG Y Corps EAP above indicates that there is an Emergency Operations Plan for the dam. The NID dam type classification includes the following types of dams: RE: rockfill/earthfill embankment dams, primarily rockfill (fill >3 size) ER: rockfill/earthfill embankment dams, primarily earthfill (fill <3 size) PG: concrete gravity dams REPG: combination dams incorporating rockfill/earthfill and concrete gravity Foster Dam is an earthfill/rockfill dam while Green Peter Dam is a concrete gravity dam. Foster and Green Peter dams were both completed in 1967; both are operated by the US Army Corps of Engineers and both have emergency operations plans in place. All Corps dams are maintained on a regular schedule and undergo regular inspections, with major reinspections every five years. Furthermore, the Corps is highly experienced in the construction, operation, and maintenance of dams. As noted previously, the NID classification as High Potential Hazard means only that there is probable loss of life if one of these dams fails. The NID classification contains no information whatsoever about the safety or lack of safety of a given dam and no information about the probability of failure. For embankment dams, as discussed above, the most common failure modes are overtopping, foundation failures, and seepage through the dam. For concrete dams, the most common failure modes are overtopping and foundation failures. Under normal or flood conditions, failure of the Corps operated dams appears highly unlikely. Failure is perhaps possible, however, in extreme flood events well above the design basis, especially if the reservoirs were close to full at the onset of flooding. The spillway capacities could be exceeded with a potential for overtopping failures. There are, however, two other circumstances that may pose significant threats to any of these dams: landslides and earthquakes. A major landslide into a reservoir, whether triggered by seismic activity or not, could result in a large surge wave that could result in dam failure from a combination of overtopping and hydrodynamic forces. A major earthquake, either a Cascadia Subduction Zone earthquake, or a smaller, interplate or intraplate earthquake in Western Oregon, could cause sufficient damage to these dams to pose a risk of failure Dam Failure Events Since the 2009 Update of the SHMP There have been no dam failure events affecting Sweet Home since completion of the 2009 update of the Sweet Home Hazard Mitigation Plan. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-6

143 12.6 Risk Assessment (Preliminary) Both of the major dams which pose a potential life safety hazard for Sweet Home are operated by the United States Army Corps of Engineers. The Portland District of the Corps, Geotechnical Engineer Branch, Concrete and Dam Safety Section has safety responsibilities for these dams. A variety of dam safety related information is also available on the Portland District s web site at Under the Corps normal dam operating practices, dams are inspected annually, with a more complete evaluation every five years on a rotating schedule Flood Damage to Dams All of the Corps dams were designed and built with specific flood capacities. Current dam designs are based on Standard Project Floods. Standard Project Floods, as defined in the Corps Engineer Manual (March 1, 1965) are floods resulting from the Standard Project Storm. In turn, the Standard Project Storm is defined, somewhat imprecisely, as the most severe flood-producing rainfall-snowmelt, depth-area-duration event that is considered reasonably characteristic of the drainage basin. Discussions with Corps staff in the Portland District Office indicated that the Standard Project Flood is approximately a 500- year flood event. The Corp dams discharge design levels include the combination of spillway discharge capacity and reservoir outlet pipe discharge capacity. As an example, for the Hills Creek Dam, the Standard Project Flood is 64,500 cubic feet per second. The maximum controlled discharge capacity of the dam is 151,760 cubic feet per second, or nearly two and one-half times the Standard Project Flood discharge. These data are included on the Hills Creek Project, Emergency Response Flowchart 7. At discharges beyond the maximum controlled discharge capacity of the dam, the dam would be overtopped, discharges would be uncontrolled, and there would be a high probability of damage to the dam, with some potential for dam failure. The large margin of safety in the discharge capacity of the dam suggests that the Hills Creek Dam likely has the capacity to withstand floods at least as large as a 1,000 year flood event without expected damage. The other Corps dams, including Foster and Green Peter, have similar margins of flood design safety Earthquake Damage to Dams Green Peter Dam and Foster Dam were the subjects of Seismic Safety Reviews (SSR) conducted by the US Army Corps of Engineers, with the 95% drafts completed in April, 2013 and July, 2013, respectively. These documents were obtained from the Corps via a Freedom of Information Act Request. A SSR is essentially a screening stage, using subjective assessment and simple preliminary analysis with existing available data to determine whether seismic safety issues exist which require a Seismic Safety Special Study (Phase I). The re-evaluation of existing project features should show that structures meet current seismic criteria. The decision to re-evaluate structures is based on changes in structural condition, seismicity, and/or technical knowledge. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-7

144 The main purpose of this Seismic Safety Review (SSR) is to reevaluate the seismic safety of the dam given the recent advances in the understanding of the seismicity of the region, which resulted in a significant increase in the expected seismic motions at the dam site. In the 1982 Earthquake and Fault Study (USACE 1982), the peak ground acceleration of 0.10g was used for the Maximum earthquake. For the Green Peter Dam, in the 2009 draft report entitled Regional Seismic Hazard Assessment: Willamette Valley in the Pacific Northwest Region (USACE 2009), the peak deterministic ground acceleration resulting from the Maximum Credible Earthquake (MCE) was estimated to be approximately 0.273g. The 2008 USGS peak probabilistic ground acceleration (2475-year event) was estimated to be approximately g. The ground motions for the Foster Dam are slightly higher with the 2008 USGS peak probabilistic ground acceleration being g. For both dams, the 2014 USGS peak probabilistic ground accelerations are very similar to the 2008 values, although about 2% or 3% lower. Thus, the current MCE levels of earthquake ground motion for these dams are more than three times higher than that assumed during the design and construction of the dams. For both dams, the seismic hazard arises from all three of types of earthquakes discussed in the earthquake chapter: Cascadia Subduction Zone Interface and Intraplate earthquakes and earthquakes on crustal faults within Oregon. The detailed conclusions and recommendations from the Seismic Safety Reviews were redacted in the reports received from the Corps. However, both dams clearly have seismic deficiencies significant enough so that the Seismic Safety Review recommended much more detailed Seismic Safety Special Studies. For both dams, the recommended studies include geotechnical investigations of the foundation stability, and structural studies of the Non-Overflow Monolith, Spillway Monolith, Spillway Gates, Spillway Pier and Powerhouse Structure. For Foster Dam, the recommendations also include structural studies of the Penstocks and Supports, Approach Channel Walls, Stilling Basin and Tailrace Walls. The Corps studies suggest that significant damage to the dams is likely in earthquakes with ground motions at the dams well above 0.10 g shaking. The extent of damage and the likelihood of damage sufficient to result in dam failure with release of impounded water cannot be estimated based on current data. For emergency planning purposes, Sweet Home should be aware of the potential inundation areas either dam were to fail and consider pro-active evacuations after earthquakes with ground motions well above 0.1 g shaking or if either dam exhibits significant damage after an earthquake. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-8

145 Loss Estimates (Preliminary) Detailed loss estimates for possible failures of Foster or Green Peter Dams are beyond the scope of the SHMP. However, the Green Peter Dam Emergency Plan includes an inundation map (September 1981) for dam failure. At Sweet Home, peak flood elevation from dam failure is estimated to be 544 feet, which is more than 8 feet higher than 100-year flood level and 3 feet higher than the 500-year flood level. The inundation area within Sweet Home includes a large area north of the South Santiam River and a narrow swath on the south side of the South Santiam River. Peak flood time is estimated to be about 2.7 hours after dam failure. Obviously, such a flood event would cause tremendous damage to property and could cause many casualties unless evacuation is both expeditious and complete. The probability of catastrophic failure of these dams is impossible to estimate with any accuracy, from present data. Most likely, the probability is less than 0.1% per year (less than once in 1,000 years, on average) and perhaps substantially less. However, the consequences of failure are so high that careful evaluation is certainly warranted. The probable impacts of potential dam failures on the City of Sweet Home are summarized below in Table Table 12-5: Probable Impacts of Potential Dam Failures on the City of Sweet Home Inventory Portion of Sweet Home affected Buildings Streets within Sweet Home Roads to/from Sweet Home Electric power Other Utilities Casualties Probable Impacts Direct impacts limited to mapped inundation areas for dam failures, or to smaller areas for more likely partial failures Heavy damage in inundation areas Damage and closures in inundation areas Damage and closures in inundation areas Damage and loss of service in inundation areas Damage and loss of service in inundation areas. Potential for major damage to water and wastewater treatment plants in extreme events Potential for high casualties (deaths and injuries) in extremely unlikely major dam failures, depending on warning time available and effectiveness of evacuations 12.7 Mitigation Strategies and Recommendations Possible dam failures affecting Sweet Home are low probability events, but the potential casualties and economic impacts are high. The combination of low probability but large impacts makes analysis of such situations difficult from both a technical and a public policy perspective. The evaluation is difficult technically because it requires detailed engineering analysis of each dam and careful probabilistic risk analysis. As always, communication with the public must be non-alarmist, but factual, realistic and informative. Recommendations are listed below (source: K. Goettle and Associates): 1. The first step in mitigation planning for dam safety is emergency planning. Emergency planners in Sweet Home should obtain copies of the inundation maps for each of the major dams to familiarize themselves with the areas of potential flooding. For emergency planning, the estimated flood depths and the time periods from dam failure are particular important. Flood depths and flood times both vary markedly with distance downstream from the dam locations. For emergency City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-9

146 planning, key elements include community emergency notification procedures and evacuation planning (routes and traffic control). Because of the very large numbers of potential evacuees, training seminars and scenario exercises are strongly recommended. 2. Both dams have Emergency Action Plans. These plans should be reviewed to ensure that they are complete and up to date. Emergency planning officials in Linn County should be fully informed of the detailed consequences of the potential failure of each dam. Public notification and evacuation plans should be updated and tested. For some types of dam failures, for example, those due to extreme floods, there may be some warning time. Decision making procedures, protocols, and procedures for issuing watches, warnings, and evacuation notices should be reviewed and updated and coordinated among all responsible federal, state, and local agencies. 3. Because of the age of Foster and Green Peter Dams, the seismic design basis is significantly below current seismic design requirements. Preliminary seismic evaluations have been done but without sufficient detail to evaluate the probabilities of dam failures. Because of the extreme consequences of potential failure of one or more of these dams, we recommend that detailed seismic evaluations be conducted for both dams. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-10

147 OG 1-2 Yrs Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 12-7 contains dam mitigation action items from the master Action Items in Chapter 4. Table 12-6: Dam Failure Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Dam Failure Mitigation Action Items ST #1 Obtain maps of dam failure inundation areas and update emergency response plan. US Corps of Engineers; City USACE X X X ST #2 Encourage US Corps of Engineers to complete seismic vulnerability assessments for Green Peter and Foster dams & make seismic improvements as necessary. US Corps of Engineers; City USACE X X X Same as Table 4-9 in Chapter 4, page G-1 G-2 G-3 G-4 G-5 G References 1. FEMA, Federal Guidelines for Dam Safety: Hazard Potential Classification Systems for Dams, FEMA 333, October FEMA, Multihazard Identification and Risk Assessment, A Cornerstone of the National Mitigation Strategy, Chapter 20, Dam Failures, FEMA, Dam Safety: An Owner s Guidance Manual, FEMA 145, August National Research Council, Safety of Existing Dams, Evaluation and Improvement, National Academy Press, FEMA website ( National Dam Safety Program webpage. 6. Oregon Emergency Management Division, Dam/Levee Failure, Statewide Hazard Analysis, March, Hills Creek Lake Project, Emergency Response Flowchart, Distributed January 2000, United States Army Corps of Engineers, Portland District, 5 pages. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 12-11

148 13.1 Overview 13.0 Disruption of Utility and Transportation Systems The previous chapters dealt with each of the major natural hazards impacting Sweet Home, including floods, severe storms, landslides, wildland/urban interface fires, earthquakes and volcanic hazards. These chapters evaluated each of the hazards and the risk arising from the hazards as they impact the buildings, infrastructure and people of Sweet Home. Each of these hazards may result in not only damage to buildings but also damage to and disruption of utility and transportation systems. Mitigation projects may be formulated to reduce or avoid such damage and disruptions and a few examples were discussed in the previous chapters. In this sense, evaluating the potential damage and disruption of utility and transportation systems from each hazard is part of the risk assessment for each locality affected by a hazard. However, disruption of utility and transportation systems may have impacts on the affected community which are far broader than the direct damage and corresponding direct loss of service. In this sense, disruption of utility and transportation systems may be viewed almost as a hazard. As for other hazards, the probability, duration, and extent of such outages can be assessed and the impacts (risk) associated with such outages can be quantified. Among the major utilities, loss of electric power generally has the most widespread impact on other utilities and on the community as a whole. Therefore, this chapter deals with electric power outages in more detail than for the other utility and transportation systems Transportation Systems Streets, roads, and highways are subject to closure during flood events because of high water levels on road surfaces. This type of closure may occur during either a major flood event on the larger rivers and streams in Sweet Home and surrounding areas or during severe storms as a result of localized flooding on smaller drainage systems. In major floods or major winter storms, such road closures may be widespread. If flow velocities are low, then such closures are usually due primarily to water depth and there is generally little damage to the road system; reopening the road simply requires waiting for the water level to drop and then cleaning up mud and debris on the road surface. However, if flow velocities are higher then erosion of the road surface or undermining of the road may occur. This type of damage is most common in hilly areas with relatively steep slopes and occurs most often on smaller roads rather than on major highways. Reopening such roads requires repair of the damaged road surface. The flood of February 1996 provided ample evidence of the impact of flooding on roads. For example, in Linn County alone, there were over 70 flood-caused road closures. These closures included major routes such as US 20 at Suttle Lake, US 99E at several sites, US 99W at Highway 47, Highway 34 at a number of locations, Highway 226 between Scio and Lyons, Highway 228 between Brownsville and Interstate 5 and many others. At the peak of the 1996 flooding, Sweet Home was largely cut-off because all of the major roads to/from Sweet Home were closed. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-1

149 Some sites of road closures are difficult to mitigate without large scale flood control projects. However, mitigation is possible at many locations with high potential for road closures. Common measures include raising the road surface to reduce the probability of water overtopping the road or improving local drainage (e.g., culvert upsizings). Risk assessments for road closures must include a measure of the importance of the road for transportation as well as an evaluation of the direct physical damages to the road. In many cases, the disruption of transportation has a larger economic impact that the direct physical damages. To evaluate and prioritize hazard mitigation projects for roads, we suggest three measures of the relative importance of a road: 1) number of vehicle trips per day, 2) detour time around a road closure, and 3) road use as primary access/egress, including emergency vehicles. The number of vehicle trips per day is an obvious measure of the importance of a road. All other factors being equal, a road with 500 trips per day is more important than a road with 50 trips per day and thus should have a higher priority for mitigation projects. However, a better measure of the importance of a road is obtained if the detour time is also considered. If traffic loads were equal, a mitigation project on a road where a closure required a one hour detour would have a higher priority than a road where a closure only required a five minute detour. More accurately, it is the combination of traffic load and detour time that provides a measure of the impact of road closure. The product of number of trips per day and the detour time gives a measure of the number of vehicle-hours of delay that result from a closure. Consider the following example: Table 13.1: Calculation of Vehicle-Hours of Delay from Road Closures Road Trips per Day Detour Time (hours) Vehicle-Hours of Delay per day of Closure A B In this example, Road A has fives times the traffic of Road B, but because the detour time is much longer for a closure on B than on A, the number of vehicle-hours of delay is greater on Road B and on Road A. On this basis, mitigation of the hazard causing the closure would have a higher priority on Road B than on Road A. The number of vehicle hours of delay is a proxy for the economic impact of the closure. The current FEMA value (for benefit-cost analysis purposes) for the economic impact of lost time due to road closures is $32.23 per vehicle hour of delay (What is a Benefit?, FEMA 2001). This value is based on national average wage and benefits level and national average vehicle occupancy data, along with the assumption that an hour of leisure time is worth the same to a person as an hour of work (a common economic assumption). Then, for example, 100 vehicle hours of delay per day has an estimated economic impact of $3,223 and so on. For the vast majority of roads, with typical traffic loads, using an economic value of $32.23 per vehicle per hour of delay provides a reasonable measure of the economic impact of road closures. Everything else being more or less equal, roads which serve as primary access/egress routes and/or serve many emergency vehicles may be given a higher priority for mitigation. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-2

150 For completeness, we note that roads are networked systems and a more accurate analysis of the relative priority of mitigation projects to reduce road closures should consider the network characteristics of a local road system. However, network analysis is complex, requires specialized expertise and is expensive. Network analysis may be justified for very expensive projects, such as a multi-million dollar relocation of a bridge to reduce the potential for flood washouts. However, the simple three parameter prioritization methodology suggested above is probably sufficient for evaluation of most small to medium sized mitigation projects. Rail systems are subject to the same sorts of closures as are road systems. Evaluation and prioritization of mitigation projects for rail systems would follow a methodology closely analogous to that discussed above for road systems, with economic impact parameters appropriate for a rail system. Other transportation systems (air, ports, ferry) are also subject to disruption due to the impacts of hazards. The analysis of such systems is roughly similar to that discussed above, but mitigation projects for such systems are encountered far less frequently than are mitigation projects for roads. Moreover, such projects are not directly applicable to Sweet Home. Such facilities are not considered further Utility Systems - Overview Evaluation of hazard mitigation projects for utility systems have some commonalities between systems that we briefly review before addressing each major utility system in turn. Utility systems such as potable water, wastewater, natural gas, telecommunications, and electric power are all networked systems. That is, they consist of nodes and links. Nodes are centers where something happens - such as a pumping plant, a treatment plant, a substation, a switching office and the like. Links are the connections (pipes or lines) between nodes. Risk assessments for utility systems are similar to risk assessments for buildings, in that the inventory of utility components is overlaid on the hazard map and the vulnerability of utility components is evaluated for the hazards impacting the utility. A major difference arises, however, because of the networked nature of utilities. As a simple example, consider an electric utility which suffers damage to 10% of its transmission lines. The extent of service outage might be essentially zero if there are redundant lines with sufficient capacity to handle the demand for electric power. Or, the extent of service outage might be 100% if the damaged lines provide the sole power feed for a community. Thus, the operating characteristics and network characteristics (especially the amount of redundancy) must be considered. In conducting risk assessments or evaluating hazard mitigation projects for utility systems, the networked nature of such systems must be considered. The extent or lack of redundancy for particular elements in a system profoundly affects the extent to which a given level of damage results in system outages. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-3

151 The general procedure for conducting a risk assessment or evaluating a hazard mitigation project for a networked utility system is outlined below in six steps. 1) Overlay utility system components with hazard maps, 2) Estimate the vulnerability of each component to impacts from each hazard, 3) From the estimated amount of damage to the system and the system s network operating characteristics, estimate the extent and duration of service outage, 4) From the damage estimates and the resources available, estimate the restoration time, 5) From the service outage (number of customers and duration) estimate the economic impacts of such loss of service, and 6) If a mitigation project is being evaluated estimate the reduction in direct damages and the reduction in service interruption attributable to mitigation project. An important caveat for conducting risk assessments or evaluation of hazard mitigation projects for networked utility systems is that specialized expertise is often required. The analyst must thoroughly understand the operating characteristics of utility system components and their vulnerability to each hazard as well as thoroughly understand the network operating characteristics of the system as a whole. In the absence of sufficient experience and expertise risk assessments or evaluation of hazard mitigation projects may produce inaccurate and misleading results. CAVEAT: conducting risk assessments or evaluation of hazard mitigation projects of networked utility systems often requires specialized expertise to produce meaningful results. For reference, a detailed discussion of how to evaluate seismic hazard mitigation projects for water systems is given in the American Society of Civil Engineers monograph Guidelines for the Seismic Upgrade of Existing Water Transmission Facilities, (J. M. Eidinger, editor, 1999; chapter by K. A. Goettel Seismic Upgrades of Water Transmission Systems: When Is It Worth It? ). Very similar principles apply to evaluating hazard mitigation projects for other utility systems for any type of hazard. The following sections briefly review utility systems with emphasis on identifying the system components which are most vulnerable to damage and loss of service from hazards covered in this Mitigation Plan: flooding, severe storms, landslides and earthquakes. Such components are thus logical targets for high priority mitigation projects whenever important components are subject to the hazards. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-4

152 13.4 Potable Water Systems Water treatment plants, including Sweet Home s, are often located in flood prone areas and are subject to inundation when raw water enters the filters, sedimentation or flocculation basins, resulting in loss of capability to treat incoming raw water properly. Water system control buildings and pump stations may also be subject to flood damages. Public or private water systems with wells as the water source are subject to outages when flood waters contaminate well heads; this is a common problem for smaller water systems. Water transmission or distribution pipes are rarely damaged by flood waters, unless there are soil settlements or major erosion, because the lines are sufficiently pressurized (for water quality) to prevent intrusion of flood waters. Water transmission or distribution pipes are, however, subject to breakage when they cross landslide areas or in earthquakes. Water treatment plants are also subject to earthquake damages to the building and to process and control equipment. Water systems, including the Sweet Home water system, are also highly vulnerable to electric power outages. Many water systems are pumped storage systems where water is pumped to storage tanks which are typically located 60 to 200 feet above the elevation of water system customers. Such tanks generally contain no more than 1 or 2 days of storage beyond typical daily usage (for reasons of water quality). Thus, electric power outages of more than 1 or 2 days may result in loss of potable water due to the inability of pumping plants to pump water. The most logical mitigation projects to minimize such outages are to provide back-up generators at key pumping plants or to provide quick connects so that portable generators (if available) can be quickly installed. Water treatment plants are also subject to outages due to loss of electric power. Common mitigation projects for water systems include flood protection for treatment plants, providing back-up power, moving pipes from active landslide areas, and seismic upgrades for treatment plants Wastewater Systems Wastewater systems are often highly vulnerable to flood impacts. Rising water may cause collection pipes to backup and overflow. Intrusion of storm water into collection systems may results in flows that exceed treatment plant capacities, resulting in release of untreated or only partially treated flows. Treatment plants are often located in flood plains, at low elevations, to facilitate gravity flow. However, such locations also facilitate flood damages. Wastewater treatment plans may be inundated, resulting in full or partial plant shutdown or plant bypass with corresponding release of untreated or only partially treated flows. Lift stations and treatment plants are also subject to loss of function due to electric power outages, with resulting overflows or releases. Collection pipes are also subject to breakage due to landslides. However, such impacts are not particularly common, since most wastewater collection systems are in more urbanized areas with only selected areas subject to slides. Wastewater pipes are, however, subject to breakage in earthquakes. Wastewater treatment plants are also subject to earthquake damages to the building and to process and control equipment. Common mitigation projects for wastewater systems include flood protection for wastewater treatment plants, providing back-up power for nodes such as lift stations, moving collection pipes from active landslide areas, and seismic upgrades for treatment plants. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-5

153 13.6 Natural Gas Systems Natural gas transmission and distribution pipes are not usually affected by flooding, because the pipes are pressurized. However, compressor stations may be subject to inundation damage or loss of electrical power to run electrical and mechanical equipment. Transmission and distribution pipes are also subject to rupture in slide areas. Buried utility pipes are very subject to failure in small ground movements. Movements as small as an inch or two are often sufficient to break relatively brittle pipe materials. Possible mitigation projects for natural gas systems include providing back-up power for important nodes (e.g., compressor stations) and moving pipes from active landslide areas Telecommunications Systems Telephone (land lines and cellular) systems, broadcast radio and TV systems, and cable TV systems may all be vulnerable to damages and services outages from hazards. However, in general, such systems have proved to be somewhat less vulnerable to service outages than other utility systems. System nodes (broadcast studios, switching offices and such) are subject to flooding if located in flood-prone areas. However, because of the importance of such facilities, few are located in highly flood-prone sites. Similarly, few such facilities are likely to be located in landslide prone areas. Cellular towers in hilly areas, however, may be more subject to landslide hazards. Buried communications (copper and fiber optic) and cable television cables are usually flexible enough to accommodate several feet of ground movement before failure. Thus, while major landslides may rupture such cables, minor settlements or small slides are not nearly as likely to impact such cables as they are to break buried gas or water pipes. Above ground communications and cable television cables are subject to wind-induced failures from tree falls and pole failures. However, such failures are about ten times less common than failures of electric power lines. The better performance of communications cables arises in part because the electrical cables are always highest on the poles, thus a falling branch is usually first resisted by the power cables. Also, because the voltage levels in communications cables are much lower than those in power cables, the communication cables are not subject to burn down or shorting if wind-swayed cables touch each other or get too close. Some telecommunications facilities are subject to failure as a result of loss of electric power. However, key facilities almost always have backup battery power and/or generators. Therefore, telecommunications facilities are generally much less vulnerable to outages from loss of electric power than are water or wastewater systems. Possible mitigation projects for telecommunications systems include flood proofing of important nodes, adding back-up power, relocating facilities out of active slide areas and seismic retrofits. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-6

154 13.8 Electric Power Systems The electric power system is central to the functioning of a modern society. The impacts of loss of electric power are large: residential, commercial and public customers are all heavily dependent on electric power for normal functioning. Furthermore, as discussed above, other utility systems, especially water systems, are heavily dependent on electric power for normal operations. Loss of electric power, therefore, may have large impacts on affected communities, especially if outages are prolonged. The Regional All Hazard Mitigation Plan for Benton, Lane, Lincoln and Linn Counties included reviews of the operating characteristics of electric power systems and the major failure modes (see Regional Mitigation Plan, Phase One, Technical Appendix). We briefly summarize this information here. Electric systems have three main parts: generation, transmission, and distribution. Generation is the production of electric power. Generating plans can be hydroelectric, fossil fuel (oil, gas, or coal), nuclear, or various renewable fuels (wind, solar, biomass, etc.). Most of the electric power consumed within Linn County is thus produced elsewhere and transmitted via high-voltage transmission lines. The Bonneville Power Administration (BPA) is the primary source of power for Linn County. BPA s power comes from hydroelectric facilities (57%) operated by the Corps of Engineers or the Bureau of Reclamation, from a nuclear plant (3%) operated by the Washington Public Power Supply System (WPPSS), from interchanges and wheeling (37%) of power transmitted by BPA but not owned by BPA and from other sources (3%). Through the Pacific Interties (high voltage AC or DC transmission lines) power is moved back and forth between California, the Pacific Northwest and western Canada. The transmission system is a network of high voltage lines (500 kv and 230 kv) and substations which transmit power between generation plants and the local distribution system. The distribution system is a network of lower voltage lines and substations which carries power from transmission system substations to neighborhoods and eventually to individual customers. Power outages in Linn County are most likely from disruption of the transmission lines carrying power from outside Linn County or within Linn County, or damage to the local distribution lines within Sweet Home. The generating plant system has sufficient redundancy so that failures of one or more plants do not usually lead to significant power outages. However, because of the limited generation capacity within Linn County, major disruptions in the transmission system would result in substantial curtailment of available power. A major ice storm in the Columbia River area could conceivably fail all of the 500 kv transmission lines feeding Linn County from the north. However, the transmission system has enough redundancy that the power needs of Linn County would likely be met by a combination of local generating capacity and transmission of power from California. However, a severe ice storm with 2 to 4" of ice over much of Linn County could result in failure of all north-south 500 kv and 230 kv transmission lines within Linn County. Such a failure, which is unlikely, but certainly not impossible, would probably entail widespread power outages for 2 to 5 days. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-7

155 The most frequent power outages, however, are due to failure of the local subtransmission or distribution system lines. Severe storms are the most frequent cause of significant electric power outages, with wind being the primary culprit. Electric distribution lines, the low voltage lines that deliver power to neighborhoods, are the most vulnerable electric system component in severe storms. Failures most commonly result from tree falls or from burn downs when wind-swayed cables touch or get too close to each other and short circuit. Distribution system failures may also be due to utility pole failures. Distribution lines may also fail due to ice loading in excess of design specifications or from landslides or debris flows or flooding which knock out utility poles. Failures of distribution system lines are thus the most common failure mode for electric power systems. Power system outages are more common and of longer duration in rural areas compared to urban or suburban areas. Rural areas are more prone to electric outages because they have a higher percentage of above-ground lines and are more likely to have hilly areas with high concentrations of trees and higher wind speeds than in flatter terrain. In rural areas, with lower population density, there is also a higher ratio of length of distribution lines per customer. With a longer length of exposed line, the probability of an outage is higher for a rural customer than for an urban customer. Once a portion of a power distribution circuit fails, all customers in that part of the circuit lose power. The duration of the power outage depends on the number of outages and the number of repair crews available for repairs. A typical power utility repair crew (2 or 3 people with a cherry picker) can restore power to a distribution circuit with common types of damage in 1 or 2 hours after arriving at the damage site. Electric transmission lines (110 kv and higher) are less vulnerable to severe storm damage because of more robust design specifications. Also, such lines are usually higher above the ground and much less prone to tree branches falling on lines. Furthermore, because of the higher voltage (compared to distribution lines), power utilities must diligently pursue tree trimming programs to avoid flashovers from lines being too close to trees. Nevertheless, transmission lines do sometimes fail due to large tree falls, rapid growth of trees near lines, unusually high winds or heavy ice loads. Sweet Home is subject to outages of electric power primarily due to line failures. The most common failure modes would be the transmission lines that feed Sweet Home along Highways 20 and 228 from the west and southwest, failures of the trunk distribution lines within Sweet Home and failures of distribution circuits or service drops from distribution lines to individual buildings. All of these failures are most likely due to tree falls during wind storm events. Mitigation projects to reduce the frequency and duration of electric power systems include: augmenting tree trimming programs and hardening lines and poles in locations where ice loading or wind effects result in repeated outages. In some cases, adding connections to improve redundancy of power feed paths and adding disconnect switches to minimize areas affected by any given failure are also worthwhile. In addition to such hard mitigation possibilities, there are also soft or planning mitigation projects. For example, enhancing mutual aid agreements with nearby utilities can reduce the duration of major outages by increasing the number of crews and equipment for making repairs. Other planning/logistics measures such as ensuring that adequate supplies of parts and equipment are available may also reduce the duration of future outages. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-8

156 For Sweet Home, augmenting tree trimming programs, especially for the transmission lines and the trunk distribution lines, is probably the most effective mitigation measure. In selected locations upgrading lines and poles to better withstand loads from trees, wind and ice may also be appropriate. If there are key links in the systems that are highly prone to repetitive failures, undergrounding of limited portions of such links may also be appropriate Probable Impacts on City of Sweet Home The probable impacts of disruption of utility and transportation systems on the City of Sweet Home are summarized below in Table Table 13-2: Probable Impacts of Disruption of Utility and Transportation Systems on the City of Sweet Home Inventory Portion of Sweet Home affected Buildings Streets within Sweet Home Roads to/from Sweet Home Electric power Other Utilities Casualties Probable Impacts Impacts may be localized for damage to local utility distribution systems or street closures, or effect the entire City for damage to transmission lines or closures of major highways to/from Sweet Home Negligible impacts to buildings, but loss of utilities may substantially affect function of buildings Some incidents may include temporary street closures Some incidents may include temporary road closures Some incidents may include temporary loss of electric power in localized parts of Sweet Home or for the entire City. Duration of disruptions can range from an hour to up to a probably maximum outage of 1 or 2 days. Some incidents may include temporary loss of utilities in localized parts of Sweet Home or for the entire City. Duration of disruptions can range from an hour to up to a probably maximum outage of 1 or 2 days. Low potential for direct casualties, but some incidents such as loss of electric power during cold weather may require evacuations and displacement of people (especially fragile or special needs population) to temporary shelters Transportation or Utility Disruptions Since the 2009 Update of the SHMP There have been no significant disruptions of transportation or utility systems affecting Sweet Home since completion of the 2009 Sweet Home Hazard Mitigation Plan. However, it is worth noting that on several occasions (including the winter of ) when portions of the community have experienced electrical power outages for several hours as a result of a variety of reasons, some of which were directly attributable to severe storms. None of the outages have been for prolonged periods of time Mitigation Action Items Table 13-3 contains mitigation action items for mitigation of disruption of utility and transportation systems from the master Action Items in Chapter 4. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-9

157 1-2 Years OG 5 Yrs 5 Yrs 5 Yrs OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built -Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 13-3: Mitigation Action Items for Disruption of Utility and Transportation Systems Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Utility and Transportation System Disruption Mitigation Action Items ST #1 Same as ST#4 in Table 4-2, and ST#1 and LT#3 in Table 4-4. (Addresses Critical Facilities and Emergency Shelters.) Same City X X X X LT #1a Create an emergency potable water filling station. CPWD City, FEMA X X X LT #1b Obtain/have available a portable potable water source (e.g., tank truck, tender) for emergency water deliveries. CPWD City X X X LT #2 Have a list of contact information and establish procedures for enhancing communications with and engaging the services of the Amateur Radio Emergency Services (ARES) in SH. CCDD; Linn Co. Emergency Services; ARES City, Linn County X X X X LT #3 Educate and encourage residents to maintain several days of emergency supplies for power outages or road closures. SHMPC City X X X X LT #4 Increase the fuel storage capacity for emergency backup generator at wastewater treatment plant and reinstating fuel station at PW Maintenance Shops for City vehicles during emergencies. CPWD City X X X Same as Table 4-10 in Chapter 4 page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 13-10

158 14.1 Introduction 14.0 Hazardous Materials For mitigation planning, hazardous materials may be defined simply as any materials that may have negative impacts on human health. That is, exposure to hazardous materials may result in injury, sickness, or death. The impacts of hazardous materials may be short-term with negative effects immediately or in a few seconds, minutes or hours or long-term with negative effects in days, weeks, or in some cases years after exposure. Hazardous materials vary widely in their toxicity to humans. Some hazardous materials are highly toxic so that even brief exposures to small amounts may be dangerous or even fatal. Other hazardous materials are much less toxic and negative effects may occur only after exposure to large amounts over a longer time period. The technical term toxic, which is widely used to describe hazardous materials, is simply a synonym for the more common terms poison or poisonous. Hazardous chemicals are widely used in heavy industry, manufacturing, agriculture, mining, the oil and gas industry, forestry, and transportation as well as in medical facilities and commercial, public and residential buildings. There are literally hundreds of thousands of chemicals that may be hazardous to human health, at least to some extent. A typical single family home may contain dozens of potentially hazardous materials including fuels, paints, solvents, cleaning chemicals, pesticides, herbicides, medicines and others. However, for mitigation planning, purposes, small quantities of slightly or moderately hazardous materials being used by end users are rarely the focus of interest. Rather, interest is focused primarily on larger quantities of hazardous materials in industrial use and on hazardous materials being transported, where the potential for accidental spills is high. Situations involving extremely hazardous materials or large quantities of hazardous materials in locations where accidents may result in significant public health risk are of special concern for planning purposes. For mitigation planning purposes, the toxicity of particular hazardous materials is an important measure of the potential impact of hazardous materials on affected communities, but not the only important measure. Other characteristics of hazardous materials, especially the quantity of material and the ease of dispersal of the material may be as important as or more important than toxicity in governing the level of potential threat to a community. For example, a small quantity of a very toxic solid hazardous material in a research laboratory may pose a much smaller level of risk for a community than a large quantity of a less toxic gaseous material in an industrial site upwind from a populated area. The severity of any hazardous material release incident for an affected community depends on several factors, including: a) the toxicity of the hazardous material, b) the quantity of the hazardous material released, c) the dispersal characteristics of the hazardous material, d) the local conditions such as wind direction and topography, and e) the efficacy of response and recovery actions. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-1

159 14.2 Effects of Hazardous Materials on Humans There are three principal modes of human exposure to hazardous materials: 1) Inhalation of gaseous or particulate materials via the respiratory (breathing) process, 2) Ingestion of hazardous materials via contaminated food or water, and 3) Direct contact with skin or eyes. Exposure to hazardous materials can result in a wide range of negative health effects on humans. Hazardous materials are generally classified by their health effects. The most common classes of hazardous materials are summarized below. 1. Flammable materials are substances where fire is the primary threat, although explosions and chemical effects listed below may also occur. Common examples include gasoline, diesel fuel, and propane. 2. Explosives are materials where explosion is the primary threat, although fires and chemical effects listed below may also occur. Common examples include dynamite and other explosives used in construction or demolition. 3. Irritants are substances that cause inflammation or chemical burns of the eyes, nose, throat, lungs, skin or other tissues of the body in which they come in contact. Examples of irritants are strong acids such as sulfuric or nitric acid. 4. Asphyxiants are substances that interfere with breathing. Simple asphyxiants cause injury or death by displacing the oxygen necessary for life. Nitrogen is a good example. Nitrogen is a normally harmless gas that constitutes about 78% of the atmosphere. However, nitrogen release in a confined space may result in asphyxiation by displacing oxygen. Chemical asphyxiants are substances that prevent the body from using oxygen or otherwise interfere with the breathing process. Common examples are carbon monoxide and cyanides. 5. Anesthetics and Narcotics are substances with act on the body by depressing the central nervous system. Symptoms include drowsiness, weakness, fatigue, and incoordination, which may lead to unconsciousness, paralysis of the respiratory system and death. Examples include numerous hydrocarbon and organic compounds. Much of the information in this section has been summarized from Chapter Six of the Handbook of Chemical Hazard Analysis Procedures 1. The first few chapters of this handbook contain a concise summary of many of the technical aspects of hazardous materials. These chapters may be useful to readers seeking a more technical introduction to the nomenclature and science of hazardous materials. Hazardous materials may also have a wide variety of more specialized impacts on human health. Other types of toxic effects are briefly summarized below in Table City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-2

160 Table 14-1: Other Types of Hazardous Materials Type of Hazardous Material Hepatotoxin Nephrotoxin Neurotoxin Carcinogen Mutagen Teratogen Radioactive materials Infectious substances Effects on Humans Liver damage Kidney damage Neurological (nerve) damage May result in cancer May produce changes in the genetic material of cells May have adverse affects on sperm, ova, or fetal tissue May result directly in radiation sickness at high exposure levels or act as carcinogen, mutagen, or teratogen Biological materials such as bacteria or viruses that may cause illness or death 14.3 Classification System and Emergency Response Protocols A standardized system is used to classify and identify hazardous materials. The Emergency Response Guidebook * outlines the classification system. This Guidebook is an extremely useful reference book that provides standardized first response protocols and detailed reference sheets for the most common classes of hazardous materials. Hazardous material releases are predominantly accidental results of traffic accidents, equipment failures or human errors. In rare cases, hazardous material releases may result from deliberate actions of sabotage or terrorism. First responders for hazardous material incidents are generally public safety personnel (police or fire). The standard protocols for first responders are briefly summarized below, following guidance in the Emergency Response Guidebook. The primary guidance for first responders is to: 1) resist rushing in, 2) approach the incident site from upwind, uphill or upstream, and 3) stay clear of all spills, vapors, fumes and smoke. Upon approaching the incident site, a three-step procedure is recommended: 1) identify the material, 2) find the materials three digit guide number, and 3) read the numbered guide carefully and respond accordingly. Identification of hazardous materials is by finding any one of the following: 1) the four-digit ID number on a placard or orange panel, 2) the four-digit ID number on a shipping document or package, or 3) the name of the material on a placard, shipping document or package. * This is a Guidebook for First Responders during the Initial Phase of a Dangerous Goods/Hazardous Material Incident 2. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-3

161 Once identified by ID number or name, the material s three-digit guide number is looked up in either the ID number index or the name index. Then, the procedures and precautions outlined in the guide for the identified class of material are carefully followed. For each class of material, the guides have critical information on potential hazards, suggested evacuation distances for small and large spills, and recommended emergency response actions, including first aid. For further technical details see the Emergency Response Guidebook. In Oregon, the Office of State Fire Marshal has defined standard response protocols for hazardous materials incidents in a series of Standard Operating Guidelines 3. This series of about a dozen standard operating guidelines covers every main aspect of emergency response and recovery, including decisions to respond, levels of response, general response guidelines, mitigation methods, decontamination procedures, personal protective equipment, and others. In Oregon, there is a three-level response plan for hazardous material incidents involving first responders and specialized emergency response teams. First responders are local staff, generally public safety staff (police and fire) that are trained in basic procedures for the initial (first) response to hazardous materials incidents. The responsibilities of first responders include securing the incident scene and making a preliminary assessment of the potential severity of the hazardous material incident and the level of threat, if any, to persons at and outside of the immediate incident area. Emergency response teams are specialized teams, composed primarily of public safety staff, with higher-level training and more specialized equipment for dealing with hazardous materials incidents than first responders. In Oregon, there are fourteen emergency response teams, each with a defined geographic area of primary responsibility. Statewide, these emergency response teams respond to about 350 hazardous material incidents per year, or about one per day, on average (Standard Operating Guidelines, Team Background 3 ). For Sweet Home, the emergency response team with primary responsibility is the HM05 Linn/Benton team with responsibility for Linn, Benton, and Lincoln Counties. The three-level response plan for hazardous materials incidents is characterized as Level I Response, Level II Response and Level III response. The distinction between Levels I, II, and III depends on: 1) class of hazardous material, 2) size of container, 3) fire/explosion potential, 4) leak severity and container integrity, and 5) threat to life safety. Level I Responses are those incidents readily controlled or stabilized by first responders. The HazMat Emergency Response Team personnel may provide technical assistance via telephone or on-site assistance, but full response by an Emergency Response Team is not required. Level II Responses are those incidents that require response from a HazMat Emergency Response Team for control or stabilization of the spill. The Emergency Response Team response level may be 2-4 personnel for identification of the material and guidance on appropriate response actions or the response level may be a small team response of 6-8 personnel. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-4

162 Level III Responses are those incidents that require special resources, including one or more full Emergency Response Teams and possibly other outside agencies for support. Further technical details of the Level I, II, and III responses are given in the Standard Operating Guidelines, Levels of Response to Hazardous Materials Incidents, T A very useful glossary of technical terms used for hazardous materials incidents is given in the Glossary of Terms (Standard Operating Guidelines, Glossary of Terms, SOG-T ) 14.4 Statutory and Regulatory Context The manufacture, storage, use, transportation, and disposal of hazardous materials are subject to a myriad of federal, state, and local regulations. In the context of mitigation planning and emergency response, we focus on reporting requirements for chemicals subject to mandatory risk management planning and extremely hazardous substances subject to additional reporting and planning requirements. Section 112(r) of the Clean Air Act Amendments was designed to prevent accidental releases of hazardous substances. The rule establishes a list of chemicals and threshold quantities that identify facilities subject to subsequent accident prevention regulations. The listed substances have the greatest potential to pose the greatest hazard to public health and the environment in the event of an accidental release. The full list of Section 112(r) chemicals, including planning threshold quantities (TPQ) is given in Appendix 1, Table A1.1 of the Regional Phase Three Plan. Hazardous materials may be released to the environment either routinely during manufacturing and other ongoing processes or accidentally. Certain types of businesses are required to report such releases annually for a specified list of chemicals. The paragraph below, quoted from the Office of State Fire Marshal, Hazardous Substance Information System (HSIS) 4, summarizes the intent and content of the regulatory requirements for substances covered under the Toxic Release Inventory regulations: The Toxics Release Inventory (TRI) Program was established by Section 113 of the Emergency Planning and Community Right to Know Act (EPCRA) of Under this program certain businesses are required to submit reports each year on the amounts of toxic chemicals their facilities release into the environment, either routinely or as a result of accidents. There are additional reporting and planning requirements for materials deemed to be extremely hazardous. The paragraphs below, quoted from the Office of State Fire Marshal, Hazardous Substance Information System (HSIS) 4, summarize the intent and content of the regulatory requirements for extremely hazardous materials: SARA Title III, section 302 requires owners and operators to notify the State Emergency Response Commission (SERC) regarding the presence of Extremely Hazardous Substances (EHS) at their facilities. Section 303 requires facilities that possess a threshold planning quantity (TPQ) of an EHS to develop a contingency plan in case of an accidental release, and assist emergency planners and emergency response organizations in developing a plan to protect the community from possible injury from a release of dangerous chemicals. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-5

163 The full list of substances designated as Extremely Hazardous Substances (EHS) is given in Appendix 1 as Table A1.3 of the Regional Phase Three Plan Fixed Site Hazardous Materials Locations in Linn County and Sweet Home The Oregon Office of State Fire Marshal maintains a comprehensive listing of hazardous materials locations in Oregon 4. Key data for Linn County and Sweet Home are shown below in Table Table 14-2: Summary of Hazardous Substance Information System (HSIS) Data County Total Reports Reportable Quantities 112(r) 1 Chemicals Sites with: 313 (TRI) 2 Chemicals EHS 3 Chemicals Linn Sweet Home Chemicals reportable under Section 112(r) 2 Chemicals reportable under Section 313,Toxics Release Inventor 3 Extremely hazardous substances For Linn County, the HSIS database has hazardous materials reports for 1558 companies and other entities such as cities and universities that have hazardous materials. Of these report locations, 739, or about 47%, have reportable quantities of hazardous materials. For Sweet Home, the HSIS database has hazardous materials reports for 144 companies and other entities, including the City of Sweet Home, that have hazardous materials. Sixty-two sites in Sweet Home have reportable quantities. As shown in Table 14.2, Sweet Home also has 33 sites with Section 112(r) chemicals, 12 sites with Section 313 Toxics Release Inventory chemicals, and 5 sites with Extremely Hazardous Substances. For mitigation planning purposes, Extremely Hazardous Substances are of special concern. The locations in Sweet Home with Extremely Hazardous Substances are shown below in Table Table 14-3: Sweet Home Locations with Extremely Hazardous Substances County Linn Linn Linn Linn ID No Company Name ODFW Sweet Home City f Sweet Home City Sweet Home City Address N River Dr 1357 Pleasant Valley Rd 1357 Pleasant Valley Rd 1357 Pleasant Valley Rd City Sweet Home Sweet Home Sweet Home Sweet Home Chemical Trade Name Formalin 37% Sulfur Dioxide Sulfuric Acid Chlorine Maximum Amount Units Gallons Gallons Gallons Gallons Most Hazardous Ingredient Formaldehyde Sulfur Dioxide Sulfuric Acid sodium hypochlorite (1,000 gallons)* * In February of 2014, the Sweet Home Public Works Director indicated that the sodium hypochlorite is for on-site chlorine generation. Sodium hypochlorite is far less hazardous than the gallons of chlorine that had formerly been stored. The City also has about 2,000 gallons of a little less concentrate of sodium hypochlorite at the Water Treatment Plant (WTP) for on-site chlorine generation. The WTP is located at th Avenue. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-6

164 The sites with EHS materials include the City s wastewater treatment plants and the ODFW Fish Hatchery. These sites have small quantities of EHS materials, including chlorine, sulfuric acid, sulfur dioxide and formalin (formaldehyde). Although the quantities are small, the toxicity of these materials dictates strict adherence to safety procedures especially for the chlorine tanks. The tanks should be secured properly for earthquakes and site security measures should ensure that deliberate release of chlorine is prevented Hazardous Materials Transport: Truck Shipments, Rail Shipments and Pipelines Hazardous materials may be transported once or many times during their life cycle of raw materials, manufacturing, incorporation in other products, wholesale and retail trade, use, waste disposal, and recycling. The transport of hazardous materials may be local within a single city or across a state, across the country or internationally. For Sweet Home, a general perspective on hazardous materials incidents is provided by annual statistics of hazardous materials incidents 5, prepared by the Office of State Fire Marshal. These incident reports include all reported hazardous material incidents, at fixed sites and during transportation, except generally excluding: 1) motor fuels which are spilled in quantities less than 42 gallons, 2) sewage overflows, 3) structure fires or other emergencies where hazardous substances are involved as exposures, if the quantities exposed are less than 42 gallons. For 2000, there were a total of 399 incidents or slightly more than one per day statewide, with only 9 reported incidents in all of Linn County. Statewide, 153 incidents, or about 37% of the total incidents occurred on roads or highways. Only 36 incidents were identified as being due to motor vehicle accident. Table 14.4: Hazardous Materials Incidents in The majority of reported incidents on roads must therefore be a result of Reported Categories of Hazardous Materials equipment failures (e.g., leaking tanks) or law enforcement actions (e.g., drug lab chemicals). Chemical Drug lab chemicals Diesel, gasoline, fuel oil Number of Incidents Most of the reported year 2000 incidents involve a relatively small number of hazardous materials, as shown below in Table These statewide data present a very useful overview of hazardous material incidents in Oregon. For Linn County and Sweet Home, the general pattern of hazardous materials is likely to be similar to the statewide pattern below. Most hazardous materials incidents in Sweet Home are likely to be the most commonly involved materials as shown below (i.e., drug lab chemicals, fuels, and motor vehicle fluids). Fuels include gasoline and diesel fuel, propane, and natural gas. Antifreeze, motor oil, hydraulic 29 fluid, transmission fluid Natural gas 45 Propane 14 No chemical involved 10 Subtotal 263 Unknown chemical 44 Red phosphorus 8 Hydrochloric acid 6 Iodine 5 Ammonia 4 Sodium hydroxide 4 Sulfuric acid 4 Chlorine 3 Transformer oil 3 Subtotal 81 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-7

165 There are 21 railroads currently operating in Oregon, according to 2002 data from the Oregon Department of Transportation website ( Addresses and contact information for all of these railroads are given on the above referenced website, as are website addresses for several of the larger railroads. The Albany & Eastern Railroad line from Albany to Sweet Home is the only railroad serving Sweet Home. This line predominantly serves the timber industry in Sweet Home, although chemicals used in lumber manufacturing and other industries are also shipped by rail. The Burlington Northern and Santa Fe railroad provided data on the numbers of carloads of hazardous materials for several segments of BNSF lines in Central Oregon data for the Albany to Sweet Home (Foster) line are given below. Table 14.5: Hazardous Materials Shipments, 1998 Burlington Northern & Santa Fe Railroad 6 Railroad Segment Albany to Foster Hazardous Commodity Number of Car Loads Poison gases 11 Corrosive materials 27 Total (as reported) 38 There are three types of major fuel pipeline systems in Linn County: 1) the Williams natural gas transmission line which runs from British Columbia, through Oregon and Washington to California, 2) natural gas distribution systems run by utilities in most cities, and 3) the Kinder Morgan petroleum products pipeline which runs from Portland to Eugene/Springfield. Neither the Williams nor Kinder Morgan pipelines run close enough to Sweet Home to affect the City. However, Sweet Home does have a natural gas distribution system within the City operated by Northwest Natural Gas. The natural gas pipeline systems of local gas utilities, including the Sweet Home system, almost always follow road and street patterns because of established utility rights of way and because of the need to connect with each building served. Thus, for areas served by natural gas, the local street network is essentially identical to the natural gas distribution pipe network. Overall, the safety record of natural gas pipelines is good with relatively few significant accidents. Natural gas is not toxic (i.e., not poisonous). However, natural gas can be an asphyxiant if it displaces oxygen in an enclosed space. Natural gas burns readily when ignited, but only when gas concentrations are between 4% and 15% in air. In its pure state, natural gas is both colorless and odorless. The strong odor normally associated with natural gas is an odorant deliberately introduced at low concentrations to serve as a warning of the presence of natural gas. The strong odorant is generally added to natural gas at the local distribution level, by local gas utilities. Fires and/or explosions from natural gas leaks in pipelines are rare. In part, the rarity of fires and/or explosions is due to the fact that natural gas is about 1/3 rd less dense than ordinary air. Thus, leaking natural gas does not accumulate near the ground or pond in low-lying areas (as heavier gases such as liquefied natural gas or gasoline fumes may do). Instead, leaking natural gas rises rapidly and is dissipated by dilution in the atmosphere. The fires City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-8

166 and /or explosions that do occur from natural gas leaks are generally in buildings where the confined space allows leaking gas to accumulate until ignited. In 2000, annual statistics of hazardous materials incidents 5, prepared by the Office of State Fire Marshal, show only 45 natural gas incidents statewide in Oregon. Pipeline breaks due to natural causes may occur due to landslides or earthquakes. Earthquake induced pipe breaks for natural gas transmission lines are most likely to occur in areas of soft soils subject to liquefaction and/or lateral spreading which cause significant pipe displacements. The most likely locations for such breaks during an earthquake are on slopes of soft ground near where pipelines cross rivers or streams. The most common man-made cause of pipeline breaks is pipeline rupture due to pipes breaking when heavy construction equipment is used to excavate for construction projects. Most such breaks occur in local distribution lines. Pipeline breaks can also be caused by deliberate actions of sabotage or terrorism. Although pipelines are not symbolic targets with political, historical, and cultural significance, they are potential targets for terrorist actions. Major pipeline breaks could disrupt gas service over wide areas with resulting significant economic impacts. Natural gas utilities and local emergency responders are generally well prepared to deal with natural gas breaks, because such incidents occur relatively frequently with well-standardized response procedures. Evacuations for natural gas pipeline ruptures are generally limited to the immediate area of the break Summary of Probable Impacts on the City of Sweet Home The probable impacts of hazmat incidents on the City of Sweet Home are summarized below in Table Table 14-6: Probable Impacts of Hazmat Incidents on the City of Sweet Home Inventory Probable Impacts Portion of Sweet Home affected Buildings Streets within Sweet Home Roads to/from Sweet Home Electric power Other Utilities Casualties Most hazmat incident impacts would be localized near source of spill, but major spills could have extensive evacuation zones and affect a significant portion of the City of Sweet Home Negligible impact, except for very near incidents which involve explosions Temporary street closures likely Temporary road closures likely Negligible impact, except for very near incidents which involve explosions Negligible impacts, except for incident which spilled hazmat into South Santiam River upstream from water intake for Sweet Home Water system (low probability of occurrence) Potential for casualties (deaths and injuries), depending on location and identify of hazmat material(s) involved, time of day and effectiveness of evacuations 14.8 Hazmat Incidents Since the 2009 Update of the SHMP There have been no significant hazmat incidents affecting Sweet Home since completion of the 2009 Sweet Home Mitigation Plan. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-9

167 14.9 Summary and Mitigation Strategies Planning and Response Hazardous materials vary dramatically in their degree of toxicity to humans. The impact of a hazardous material release incident on an affected community depends on several factors including: 1) the toxicity of the hazardous material, 2) the quantity of the hazardous material released, 3) the dispersal characteristics of the hazardous material, 4) the local conditions such as wind direction and topography, and 5) the efficacy of response and recovery actions. Effective mitigation planning and effective emergency response planning can help reduce the number or frequency of hazardous materials incidents and also reduce the severity of incidents that do occur. In combination, these benefits can significantly reduce the negative impacts of hazardous materials incidents on affected communities. The general principles of mitigation planning, emergency response planning (and training) are well standardized and practiced by Linn County and the City of Sweet Home. Perhaps the single most critical factor in enhancing both mitigation planning and emergency response planning is specific inventory awareness for major hazardous materials sites within each jurisdiction. Specific inventory awareness means detailed knowledge of the types of hazardous materials, quantities of hazardous materials and locations of every location in a jurisdiction with significant quantities of hazardous materials. In this context, what constitutes a significant quantity varies depending on the toxicity of the material, the dispersal characteristics and the nature and population of nearby areas likely to be affected by hazardous materials incidents. The Office of State Fire Marshall s Hazardous Substance Information System (HSIS) database contains a vast amount of information on the inventories of hazardous materials at fixed locations in Sweet Home. This detailed inventory information along with data hazardous materials being transported within or through Sweet Home, provides the basic data for specific inventory awareness. In combination, with the chemical data and emergency response information provided in the Emergency Response Guide and in other sources, these are the basic data necessary for effective planning and effective emergency response. The complexity and overload of information is compounded by numerous labeling, placarding, and classification systems for hazardous materials, with countless cross references to guide numbers, material safety reports and so on. Because of this vast amount of complex information, effective mitigation planning and emergency response planning must occur before an incident occurs, not after. During an incident, the most effective response is precluded and impossible to achieve if emergency personnel are thumbing through databases trying to figure out what hazardous materials are at a given location and what the appropriate response precautions and protocols are for the specific materials involved in a hazardous materials incident. Specific inventory awareness means that for every site with hazardous materials of sufficient toxicity, dispersal characteristics and quantities to pose a significant life safety risk to on-site employees and nearby residents must be identified in advance. Ideally, Sweet Home should have detailed specific inventory awareness of every significant fixed site in its jurisdiction. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-10

168 Similarly, each jurisdiction should have specific inventory awareness of the most toxic, most common, large volume shipments of hazardous materials within and through the jurisdiction. For each hazardous material deemed to pose a significant life safety threat, the necessary chemical data, response protocols, initial isolation distances, protection distances for small and large spills, and all other data necessary for safe and effective response should be compiled and readily available before incidents occur Mitigation Measures Specific inventory awareness is one cornerstone of reducing the potential for negative impacts from hazardous materials incidents by helping to optimize emergency planning and response planning. The other cornerstone is pro-active mitigation actions to reduce the number and severity of hazardous materials incidents. The most common mitigation measures for reducing the potential of damaging hazardous materials incidents are briefly summarized below Physical Safety Measures The tanks, other storage containers and transfer systems (valves, pipes etc.) for hazardous materials are frequently subject to damage in earthquakes, with a correspondingly high potential for accidental releases. Proper seismic design, bracing and anchoring of storage systems for hazardous materials can greatly reduce the potential of accidental releases during earthquakes. Bracing and anchoring measures for storage containers and transfer systems (e.g., piping) are often relatively inexpensive, with a large improvement in seismic performance. For small quantities of materials stored in bottles or jugs on shelving, bracing shelving and restraining containers so that they do not fall in earthquakes are particularly important. Over time, the storage containers and other material handling elements for hazardous materials may be changed many times. In some cases, later modifications may not be designed to the same seismic standards as the original installation or later modifications may compromise the seismic stability of the original installation. Therefore, periodic review and inspections of seismic design, bracing and anchoring are highly recommended for all hazardous material facilities. For facilities located in mapped flood plains or other areas subject to floodwaters there are two important physical safety measures. First, any containers subject to floating should be properly restrained. In many floods, improperly restrained tanks break free and float downstream, with high potential for negative impacts, including fires from tanks containing flammable materials as well as accidental releases of hazardous materials. Second, special precautions should be taken with water-reactive materials. Such materials should never be stored in low-elevation areas subject to flooding or in locations subject to water from storm water drainage or plumbing failures in a facility Standard Operating Procedures Standard operating procedures for storing, transporting, and handling hazardous materials should be strictly enforced at all facilities. Appropriate training for all staff, with review courses and appropriate protective gear are essential for safety. Rigorous inspection and enforcement of hazardous materials regulations (federal, state, and local) are an important part of the overall process of ensuring safety. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-11

169 Mitigation and Emergency Response Planning Effective pre-event mitigation planning and emergency response planning can help reduce the severity of hazardous material incidents. From the mitigation planning perspective, specific inventory awareness of the types and quantities of hazardous materials present at each facility is particular important. Local fire departments and other responders should be thoroughly familiar with the specific inventory at each facility containing hazardous materials and with the appropriate response protocols for each hazardous material. First responders and emergency response teams must both have the full range of protective gear and equipment necessary for their respective roles in responding to hazardous materials incidents. Emergency response planning should include thorough training in all aspects of hazardous materials response, including appropriate response protocols (procedures, protective gear and equipment). Frequent refresher training and frequent exercises (both tabletop and full field exercises) are essential for safe and effective emergency response. Training exercise should include both first responders and emergency response teams, to help ensure appropriate coordination of efforts during actual hazardous materials incidents. Table 14-7 contains hazardous materials mitigation action items from the master Action Items in Chapter 4. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-12

170 OG OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 14-7: Hazardous Materials Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; SHPD = SH Police Department Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Hazmat Incident Mitigation Action Items LT #1 Building on previous work, update site-specific knowledge of hazardous chemical inventories in SH including the State Fire Marshal s Community Right to Know lists so that first responders have readily available current information when needed. SHAFD; SHPD SHAFD, SHPD X X LT #2 Enhance emergency planning, agency coordination, emergency response training and equipment to address hazardous materials incidents. SHAFD; SHPD SHAFD, SHPD X X Same as Table 4-11 in Chapter 4, page G-1 G-2 G-3 G-4 G-5 G References Cited in this Chapter (Chapter Endnotes) 1. Handbook of Chemical Analysis Procedures, Federal Emergency Management Agency, U.S. Department of Transportation, and U.S. Environmental Protection Agency, U.S. Government Printing Office, Emergency Response Guidebook (A Guidebook for First Responders During the Initial Phase of a Dangerous Goods/Hazardous Material Incident), developed jointly by the U.S. Department of Transportation, Transport Canada, and the Secretariat of Transport and Communications of Mexico, Hazardous Materials Emergency Response Teams Standard Operating Guidelines, May 7, 2001 Office of State Fire Marshal (Oregon). This series of about a dozen standard operating guidelines covers every main aspect of emergency response and recovery, including decisions to respond, levels of response, general response guidelines, mitigation methods, decontamination procedures, personal protective equipment, and others. 4. Hazardous Substance Information System (HSIS), Office of State Fire Marshall, Version 1.3P, March Microsoft Access Database on CD-ROM. 5. Annual Report of Hazardous Materials Incidents in Oregon as Reported by Oregon Fire Service, Office of State Fire Marshal (Oregon), 2000 and earlier years Milepost Inventory Update Form, Burlington Northern & Santa Fe Railroad, April 30, City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 14-13

171 15.1 Overview 15.0 Terrorism For mitigation planning, terrorism is broadly inclusive of a wide range of deliberate malevolent acts intended to damage buildings, infrastructure or to result in deaths and injuries. The possibility of international terrorist organizations targeting Sweet Home, is not zero, but is certainly extremely small. However, Sweet Home is certainly subject to deliberate malevolent acts from many sources including vandals, mentally disturbed individuals, domestic terrorist groups (e.g., eco-terrorists), as well as by disgruntled residents, and past or present employees. For Sweet Home, the greatest terrorism threat is probably from eco-terrorists, because of the importance of the timber industry in the vicinity of Sweet Home, in Linn County and throughout Oregon. The range of possible malevolent actions includes vandalism, arson, explosions and armed attacks, as well as use of chemical, biological, radiological or nuclear materials. Chemical attacks include deliberate release on on-site chemicals as well as deliberate dispersal of transported hazardous materials. Biological attacks include deliberate dispersal of biologically active materials (e.g., anthrax) capable of causing sickness or death. Radiological attacks include deliberate dispersal of radioactive materials, via dirty bombs (conventional explosives laced with radioactive materials) or other methods. Nuclear attacks include explosion of nuclear devices and the radioactive fallout from such explosions. The range of possible malevolent actions also includes cyber-terrorism, or deliberate disruption/damage of computer systems and data. Especially for utility systems, cyberterrorism can also result in loss of service due to disruption/damage to automated SCADA (Supervisory Control and Data Acquisition) systems widely used by utilities Threat Spectrum For purposes of mitigation planning, we consider three sources of terrorist (malevolent) actions: outsiders, insiders, and hackers. In each case, we consider three levels of attack, with the levels reflecting the numbers of individuals involved the level of technical knowledge or expertise, and the level of equipment or tools available. This threat spectrum is summarized below in Table In Table 15-1, an outsider means anyone who is not an employee of the facility under potential terrorist attack. Outsiders could be vandals, disturbed individuals, or members of domestic or international organized groups. For Sweet Home, the most likely terrorist or malevolent acts are minor vandalism or actions by disturbed individuals or employees. Deliberate terrorist actions are most likely from domestic groups, including eco-terrorists, and are unlikely to be from international organizations. In Table 15-1, an insider means anyone who is an employee of the target under potential attack. Acts of vandalism, theft and other relatively minor actions are common. Larger scale malevolent acts are less common but still occur with some frequency. Such acts include larger scale damage, arson, explosives, and such actions as contamination of water supplies. In Table 15-1, computer hackers means individuals or groups using remote access to explore, vandalize, or destroy websites, computer databases and such. For utility systems, hackers can also impact SCADA systems and may affect system operations directly. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 15-1

172 Table 15-1: Threat Spectrum for Terrorist Actions Adversary Outsider: high level Number of Adversaries 1 to small group Outsider: medium level 1 to 3 Outsider: low level 1 or 2 Level of Knowledge Extensive knowledge of security systems, facilities and modes of attack Limited knowledge of security systems, facilities and modes of attack Minimal knowledge of security systems, facilities and modes of attack Equipment Tools hand tools, power tools, vehicles hand tools, power tools, vehicle hand tools Weapons handguns or automatic weapons, incendiary devices, explosives, contaminants handguns, incendiary devices, explosives, contaminants None Objectives Extensive damage to critical facilities, widespread damage or casualties Damage or casualties Vandalism, damage or casualties Insider: high level 1 Extensive knowledge of security systems, facilities, operations, policies and procedures On site tools, chemicals, equipment, vehicles handguns or automatic weapons, incendiary devices, explosives, contaminants Damage or casualties Insider: medium level 1 Moderate knowledge of security systems, facilities, operations, policies and procedures On site tools, chemicals, equipment, vehicles handguns, incendiary devices, explosives, contaminants Damage or casualties Insider: low level 1 Limited knowledge of security systems, facilities, operations, policies and procedures On site tools, chemicals, equipment, vehicles handgun or none Vandalism, damage or casualties Hacker: high level 1 to small group Hacker: medium level 1 or 2 Hacker: low level 1 Full knowledge of IT infrastructure, security systems, SCADA systems Sophisticated hacker tools and methods Moderate knowledge of Moderately IT infrastructure, security sophisticated systems, SCADA hacker tools systems and methods Limited knowledge of IT infrastructure, security N/A systems, SCADA systems N/A N/A N/A Destruction of data and systems, business operations Denial of servcie or disruption of some business services Minor cyber-vandalism to non-critical business areas City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 15-2

173 The probable impacts of terrorist events on the City of Sweet Home are summarized below in Table For Sweet Home, the most likely terrorist events are very small scale events (vandalism or minor damage events by insiders or local outsiders or computer hacking events), rather than major terrorist actions by outsiders. Table 15-2: Probable Impacts of Terrorist Incidents on the City of Sweet Home Inventory Portion of Sweet Home affected Buildings Streets within Sweet Home Roads to/from Sweet Home Electric power Other Utilities Casualties 15.3 Terrorism Incidents Since 2009 Probable Impacts Localized impacts for minor incidents, large portions or the entire City for extremely unlikely major incidents Localized impacts to a single building or a few nearby buildings, except for extremely unlikely major incidents Some incidents may include temporary street closures Some incidents may include temporary road closures Some incidents may include temporary loss of electric power in localized parts of Sweet Home or for the entire City Some incidents may include temporary loss of utilities in localized parts of Sweet Home or for the entire City. Major damage to water or wastewater treatment plant could result in full or partial loss of service for extended time periods Major events may result in significant casualties (deaths and injuries) There have been no terrorism acts affecting Sweet Home since completion of the 2009 update of the SHMP. This excludes minor acts of vandalism and the other type of crime common in nearly all Oregon communities; such incidents do not rise to the level of terrorism per se Mitigation Actions Evaluation of the threat of terrorist or other malevolent actions generally includes several steps: 1) determine critical facilities, 2) identify the specific adverse consequences to be avoided, 3) review the likelihood of malevolent actions, 4) evaluate existing countermeasures, and 5) implement a prioritized risk reduction plan. For Sweet Home, critical facilities include key elements of the water system, electric power substations, other facilities with hazardous materials (compare to Chapter 14) and important public facilities such as police and fire stations. The most likely adverse consequences are vandalism and minor destructive actions by outsiders, insiders, or hackers. The evaluation of existing countermeasures should include: 1) Physical security measures, such as fencing, locks and key control, structural integrity of critical assets, and detection capabilities such as intrusion detection systems, alarms, operational alarms for utility systems, and general security/access issues. 2) Cyber security measures, such as protection measures for business and operational computer systems and SCADA systems, including fire walls, access, security policies and protocols, including vendor access and system diagnostics. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 15-3

174 3) Security procedures and policies, such as personnel security, physical security, key and badge control, system control and operational data, chemical and other vendor deliveries, as well as security and emergency response training, exercises and drills. For Sweet Home, vigilance and modest upgrades to existing physical security, cyber security, and security procedures and policies are probably all that are reasonably required. The potential impacts of terrorism or other malevolent deliberate actions in Sweet Home can also be mitigated by improving emergency response capabilities. Such types of actions, such as fires or explosions, are self-evident and emergency responders are well trained for dealing with such situations. Other types of actions such as release of radiological materials, bioterrorism, or contamination of water or food supplies may not be immediately recognized. For such types of actions, close cooperation with public health officials and awareness of the possibility of deliberate actions are important. Such situations also commonly require specialized expertise and equipment to detect and identify the radiological, biological or chemical materials used in an attack. Emergency response plans should be updated and expanded, as necessary, to cover such situations, including protocols for public notifications and information about appropriate public responses such as shelter in place or evacuation. Table 15-3 contains terrorism mitigation action items from the master Action Items in Chapter 4. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 15-4

175 OG OG Coordinating Organizations Timeline Potential Funding Source(s) Reduce Threats to Life / Safety Reduce Threats to Built -Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Table 15-3: Terrorism Mitigation Action Items Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CFs = Critical Facilities; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; SHPD = SH Police Department Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Terrorism Mitigation Action Items LT #1 Building on previous work, maintain enhanced emergency planning, agency coordination, emergency response training and equipment to address terrorism incidents. [ Terrorism can include a wide variety of incidents, several of which were analyzed separately in Table 1-3 (Chapter 1, page 1-10): Terrorism per se, Weapon of Mass Destruction (WMD), Work/School Violence, and Civil Disturbance.] SHPD; SHFAD SHAFD, SHPD X X LT #2 At City-owned and/or operated critical facilities, limit accessibility (e.g., fencing, walls) to (1) sensitive systems (e.g., HVAC) and (2) sensitive parts. Encourage School District to do likewise. [City has previously made considerable progress on its CFs.] CPWD; CCDD; SH School District; SHFAD City, SHAFD, SH School District X X Same as Table 4-12 in Chapter 15, page G-1 G-2 G-3 G-4 G-5 G-6 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page 15-5

176 Overview APPENDIX 1: SYNOPSIS OF FEMA GRANT PROGRAMS FEMA FUNDING POSSIBILITIES FOR SWEET HOME For public entities, such as the City of Sweet Home, FEMA funding possibilities fall into two main categories: The post-disaster Public Assistance Program which covers not less than 75% of eligible emergency response and restoration (repair) costs for public entities whose facilities suffer damages in a presidentially-declared disaster. The Public Assistance Program also may fund mitigation projects for facilities damaged in the declared event. Mitigation grant programs (either pre-disaster or post-disaster) which typically cover up to 75% of mitigation costs. FEMA Public Assistance Program: The objective of the Federal Emergency Management Agency's (FEMA) Public Assistance (PA) Grant Program is to provide assistance to State, Tribal and local governments, and certain types of Private Nonprofit organizations so that communities can quickly respond to and recover from major disasters or emergencies declared by the President. Through the PA Program, FEMA provides supplemental Federal disaster grant assistance for debris removal, emergency protective measures, and the repair, replacement, or restoration of disaster-damaged, publicly owned facilities and the facilities of certain Private Non-Profit (PNP) organizations. The PA Program also encourages protection of these damaged facilities from future events by providing assistance for hazard mitigation measures during the recovery process. For Sweet Home, PA assistance would be available only for future presidentially-declared disaster events which resulted in damage to Sweet Home facilities. FEMA Mitigation Funding Sources The Federal Emergency Management Agency (FEMA) has several mitigation grant programs which provide federal funds to supplement local funds for specified types of mitigation activities. The FEMA grant programs typically provide 75% funding with 25% local match required; in very limited cases, FEMA grant programs may provide 90% or 100% funding. The five primary FEMA mitigation grant programs are summarized below in Table A1-1. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A1-1

177 Grant Program Table A1-1: FEMA Mitigation Grant Programs Frequency Hazard Mitigation Planning Risk Assessment Mitigation Projects Hazards Hazard Mitigation Grant Post-Disaster YES YES YES ALL Pre-Disaster Mitigation Annual YES NO YES ALL Flood Mitigation Assistance Annual YES NO YES Flood Repetitive Flood Claims Annual NO NO YES Flood Severe Repetitive Loss Annual NO NO YES Flood These FEMA grant programs have specific eligibility requirements and application deadlines. All of these grant programs have specific requirements including definitions of ineligible projects which are excluded from the grant programs. All mitigation projects (but not planning projects or risk assessments) must be cost-effective, which means that a benefitcost analysis using FEMA software and following FEMA guidance must demonstrate a benefit-cost ratio >1.0. These grant programs are not entitlement programs, but rather are competitive grant programs which require strict adherence to the eligibility and application requirements and robust documentation. Robust documentation is especially critical for the PDM grant program which is nationally competitive. The Hazard Mitigation Grant Program is initiated within a given state only after a Presidential Declaration of Disaster; thus, there is no fixed schedule. A given state may have several declarations in a given year or go several years without any declarations. Specific application deadlines are established for HMGP funds generated by each disaster declaration. The other four mitigation grant programs are annual programs with specific deadlines, which vary from year to year. However, these applications are reviewed and ranked by Oregon Emergency Management (OEM) staff before they go to FEMA for review. OEM deadlines are typically about six weeks before the FEMA deadlines. [See OEM website at The three flood-only grant programs Flood Mitigation Assistance (FMA), Repetitive Flood Claims (RFC) and Severe Repetitive Loss (SRL) are narrowly defined grant programs which apply only to properties insured under the National Flood Insurance Program (NFIP). Thus, Sweet Home would be eligible for these grants only for properties with NFIP coverage and, for the RFC and SRL programs, only if the properties also meet the repetitive loss requirements. For Sweet Home, the most likely FEMA funding sources for seismic mitigation projects are the Hazard Mitigation Grant Program and the Pre-Disaster Mitigation Program, as well as the Public Assistance Program if Sweet Home suffers damage in a future presidentially-declared disaster event. Hazard Mitigation Grant Program: The Hazard Mitigation Grant Program (HMGP) is a post-disaster grant program. HMGP funds are generated following a Presidential Disaster Declaration for a given state, with the amount of funding being a percentage of total FEMA spending for various other FEMA programs such as the Individual and Family Assistance and Public Assistance programs. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A1-2

178 FEMA regulations allow HMGP funds to be spent on any mitigation project in the state, for any hazard, regardless of whether or not an applicant was located in a declared county for a specific presidentially-declared disaster. Historically, OEM has often given priority to the declared counties and to the hazard (e.g., severe winter storms) that resulted in the presidential declaration. However, mitigation projects outside of the declared counties and for other hazards have also been considered. HMGP funds are limited to a given state. Each state manages the HMGP process, including setting state priorities and selection of projects for funding. FEMA reviews applications only to ensure that selected projects meet all of FEMA s eligibility requirements. HMGP is the most flexible grant program: grants are possible for any natural hazard and may include hazard mitigation planning and risk assessments as well as physical mitigation projects. However, states have wide latitude in setting priorities and may restrict grant eligibility to specific counties to which the disaster declaration applies and/or to specific hazards or types of mitigation activities. Thus, OEM has great influence over HMGP grants within Oregon, subject to the requirement that all grants must meet FEMA s minimum eligibility requirements. HMGP grant applications are competitive only with each state. The amount of HMGP funding in a given disaster can range from less than $100,000 to more than $1 billion for large disasters (e.g., the Northridge earthquake or Hurricane Katrina). For Oregon, declared disasters are relatively common, often with one or more declarations in a given year for severe storms, floods, or other disasters. Thus, the total amount of HMGP mitigation funds available within the state and the funds likely available for mitigation projects (absent a major hurricane or earthquake) will vary from year to year and disaster event to disaster event. HMGP mitigation grants do not have pre-set maximums on grant sizes. Pre-Disaster Mitigation Program: The Pre-Disaster Mitigation (PDM) grant program is a broad program which includes mitigation projects for any natural hazard as well as mitigation planning grants which must result in the development of a Local Hazard Mitigation Plan. PDM is a nationally-competitive annual program. The annual amount of grant funds available has ranged from about $25 million to about $250 million. The appropriation for FY 2013 was about $23.7 million. Funding levels in future years will depend on congressional appropriations. PDM grants cover 75% of the costs of mitigation projects up to a maximum federal share of $3,000,000 per project. Flood Mitigation Grant Programs: The three flood-only mitigation grant programs have annual appropriations specific to each state. As noted above, these programs are applicable only to NFIP insured properties and in addition for the RFC and SRL programs, only to properties which also meet the repetitive flood loss criteria. Each of these programs has their specific guidance, outlined in the Hazard Mitigation Assistance unified guidance discussed below. However, the overall grant requirements are similar to those for the HMGP discussed above. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A1-3

179 For Sweet Home, the likelihood of getting a Flood Mitigation Assistance grant appears modest; however, there may be a few homes or other buildings at sufficient flood risk to have elevation or acquisition projects potentially eligible for FMA grant funding.. Absent any properties on FEMA s national repetitive loss list, Sweet Home would not be eligible for either of FEMA s repetitive flood loss grant program. Mitigation Grant Guidance and Requirements FEMA s detailed program guidance and the specific requirements for each grant program are posted on the FEMA website ( ). The FEMA website contains downloadable detailed guidance for each of the five grant programs summarized above. Mitigation Project Grant Applications All of FEMA s mitigation grant programs are competitive, either within a given state or nationally. Thus, successful grant applications must be complete, robust and very well documented. The key elements for successful mitigation project grant applications include: Project locations within high hazard areas. Project facilities which have major vulnerabilities which pose substantial risk of damages, economic impacts, and (especially for seismic projects) deaths or injuries. For utility mitigation projects, the majority of benefits often accrue from reductions in the calculated economic impacts (using FEMA standard methodologies) of the loss of utility services. Mitigation project scope and budget are well documented. The benefits of the project are carefully documented using FEMA benefit-cost software, with all inputs meticulously meeting FEMA s guidance and expectations. A benefit-cost analysis meeting FEMA s requirements is very often the most critical step in determining a mitigation project s eligibility and competitiveness for FEMA grants. A further eligibility requirement for mitigation project grants is that the local applicant must have a FEMA approved local hazard mitigation plan. Sweet Home will continue to be eligible to apply for FEMA mitigation grants, once FEMA approves the updated Sweet Home Hazard Mitigation Plan. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A1-4

180 APPENDIX 2: PRINCIPLES OF BENEFIT-COST ANALYSIS Benefit-cost analysis is the tool that provides answers to a central question for hazard mitigation projects: Is it worth it? If hazard mitigation were free, individuals and communities would undertake mitigation with robust enthusiasm and the risks from hazards would soon be greatly reduced. Unfortunately, mitigation is not free, but often rather expensive. For a given situation, is the investment in mitigation justified? Is the owner (public or private) better off economically to accept the risk or invest now in mitigation to reduce future damages? These are hard questions to answer! Benefit-cost analysis can help a community answer these difficult questions. In the complicated real world of mitigation projects, there are many factors which determine whether or not a mitigation project is worth doing or which of two or more mitigation projects should have the highest priority. Consider a town which has two flood prone neighborhoods and each neighborhood desires a mitigation project. The two neighborhoods have different numbers of houses, different value of houses, different frequencies and severity of flooding. The first neighborhood proposes storm water drainage improvements at a cost of $3.0 million. The second neighborhood wants to elevate houses at a cost of $3.0 million. Which of these projects should be completed? Both? One or the Other? Neither? Which project should be completed first if there is only funding for one? Are there alternative mitigation projects which are more sensible or more cost-effective than the proposed projects? Such complex socio-political-economic-engineering questions are nearly impossible to answer without completing the type of quantitative flood risk assessment and benefit-cost analysis discussed below. In determining whether or not a given mitigation project is worth doing, the level of risk exposure without mitigation is critical. Consider a hypothetical $1,000,000 mitigation project. Whether or not the project is worth doing depends on the level of risk before mitigation and on the effectiveness of the project in reducing risk. For example, if the before mitigation risk is low (a subdivision street has a few inches of water on the street every couple of years or a soccer field in a city park floods every five years or so) the answer is different than if the before mitigation risk is high (100 or more houses are expected to have flooding above the first floor every 10 years or a critical facility is expected to be shut down because of flood damages once every five years). All well-designed mitigation projects reduce risk (badly designed projects can increase risk or simply transfer risk from one community to another). However, just because a mitigation project reduces risk does not make it a good project. A $1,000,000 project that avoids an average of $100 per year in flood damages is not worth doing, while the same project that avoids an average of $200,000 per year in flood damages is worth doing. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A2-1

181 The principles of benefit-cost analysis are briefly summarized here. The benefits of a hazard mitigation project are the reduction in future damages and losses, that is, the avoided damages and losses that are attributable to a mitigation project. To conduct benefit-cost analysis of a specific mitigation project the risk of damages and losses must be evaluated twice: before mitigation and after mitigation, with the benefits being the difference. The benefits of a hazard mitigation project are thus simply future damages and losses which are avoided because a mitigation action was implemented. Because the benefits of a hazard mitigation project accrue in the future, it is impossible to know exactly what they will be. For example, we do not know when future floods or other natural hazards will occur or how severe they will be. We do know, however, the probability of future floods or other natural hazards (if we have appropriate hazard data). Therefore, the benefits of mitigation projects must be evaluated probabilistically and expressed as the difference between annualized damages before and after mitigation. To illustrate the principles of benefit-cost analysis, we consider a hypothetical single family home in the town of Acorn, with the home located on the banks of Squirrel Creek. The home is a one-story building, about 1500 square feet on a post foundation, with a replacement value of $60/square foot (total $90,000). We have flood hazard data for Squirrel Creek (stream discharge and flood elevation data) and elevation data for the first floor of the house. Therefore, we can calculate the annual probability of flooding in one-foot increments, as shown below. Flood Depth (feet) Table A2-1: Damages Before Mitigation Annual Probability of Flooding Scenario Damages and Losses Per Flood Event Annualized Flood Damages and Losses $6,400 $1, $14,300 $1, $24,500 $2, $28,900 $ $32,100 $ $36,300 $123 Total Expected Annual (Annualized) Damages and Losses $6,312 Flood depths shown above in Table A2-1 are in one foot increments of water depth above the lowest floor elevation. Thus, a 3" foot flood means all floods between 2.5 feet and 3.5 feet of water depth above the floor. We note that a 0" foot flood has, on average, damages because this flood depth means water plus or minus 6" of the floor; even if the flood level is a few inches below the first floor, there may be damage to flooring and other building elements because of wicking of water. The Scenario (per flood event) damages and losses include expected damages to the building, content, and displacement costs if occupants have to move to temporary quarters while flood damage is repaired. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A2-2

182 The Annualized (expected annual) damages and losses are calculated as the product of the flood probability times the scenario damages. For example, a 4 foot flood has slightly less than a 1% chance per year of occurring. If it does occur, we expect about $32,100 in damages and losses. Averaged over a long time, 4 foot floods are thus expected to cause an average of about $315 per year in flood damages. Note that the smaller floods, which cause less damage per flood event, actually cause higher average annual damages because the probability of smaller floods is so much higher than that for larger floods. With these data, the house is expected to average $6312 per year in flood damages. This expected annual or annualized damage estimate does not mean that the house has this much damage every year. Rather, in most years there will be no floods, but over time the cumulative damages and losses from a mix of relatively frequent smaller floods and less frequent larger floods is calculated to average $6,312 per year. The calculated results in Table A2-1 are the flood risk assessment for this house for the as-is, before mitigation situation. The table shows the expected levels of damages and losses for scenario floods of various depths and also the annualized damages and losses. The risk assessment shown in Table A2-2 shows a high flood risk, with frequent severe flooding which the owner deems unacceptable. He explores mitigation alternatives to reduce the risk: the example below is to elevate the house 4 feet. Flood Depth (feet) Table A2-2: Damages After Mitigation Annual Probability of Flooding Scenario Damages and Losses Per Flood Event Annualized Flood Damages and Losses $0 $ $0 $ $0 $ $0 $ $6,400 $ $14,300 $49 Total Expected Annual (Annualized) Damages and Losses Total Expected Annual (Annualized) Damages $112 By elevating the house 4 feet, the owner has reduced his expected annual (annualized) damages from $6,312 to $112 (98% reduction) and greatly reduced the probability or frequency of flooding affecting his house. The annualized benefits are the difference in the annualized damages and losses before and after mitigation or $6,312 - $112 = $6200. Is this mitigation project worth doing? Common sense says yes, because the flood risk appears high: the annualized damages before mitigation are high ($6,312). To answer this question more quantitatively, we complete our benefit-cost analysis of this project. One key factor is the cost of mitigation. A mitigation project that is worth doing at one cost may not be worth doing at a higher cost. Let s assume that the elevation costs $20,000. This $20,000 cost occurs once, up front, in the year that the elevation project is completed. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A2-3

183 The benefits, however, accrue statistically over the lifetime of the mitigation project. Following FEMA convention, we assume that a residential mitigation project has a useful lifetime of 30 years. Money (benefits) received in the future has less value than money received today because of the time value of money. The time value of money is taken into account with present value calculation. We compare the present value of the anticipated stream of benefits over 30 years in the future to the up-front out-of-pocket cost of the mitigation project. A present value calculation depends on the lifetime of the mitigation project and on what is known as the discount rate. The discount rate may be viewed simply as the interest rate you might earn on the cost of the project if you did not spend the money on the mitigation project. Let us assume that this mitigation project is to be funded by FEMA, which uses a 7% discount rate to evaluate hazard mitigation projects. With a 30-year lifetime and a 7% discount rate, the present value coefficient which is the value today of $1.00 per year in benefits over the lifetime of the mitigation project is That is, each $1.00 per year in benefits over 30 years is worth $12.41 now. The benefit-cost results are now as follows. These results indicate a benefit-cost Table A2-3: Benefit-Cost Results ratio of Thus, in FEMA s terms Annualized Benefits $6,200 the mitigation project is cost-effective and eligible for FEMA funding. Taking Present Value Coefficient into account the time value of money Net Present Value of Future Benefits $76,942 (which is essential for a correct Mitigation Project Cost $20,000 economic calculation) results in lower Benefit-Cost Ratio 3.85 benefits than if we simply multiplied the annual benefits times the 30 year project useful lifetime. Economically, simply multiplying the annual benefits times the lifetime would ignore the time value of money and thus gives an incorrect, spurious result. The above discussion of benefit-cost analysis of a flood hazard mitigation project is intended to illustrate the basic concepts. Very similar principles apply to mitigation projects for earthquakes or any other natural hazards. However, for tornado and earthquake mitigation projects, one of the major benefits is life safety. For purposes of benefit-cost analysis, the statistical values for deaths and injuries must be included in the benefit-cost analysis. For reference, the recent FEMA statistical value for human life was about $5.8 million 1. Given this high value, many tornado shelter mitigation projects and many seismic mitigation projects are deemed cost-effective and thus eligible for FEMA hazard mitigation grant funding. The role of benefit-cost analysis in prioritizing and implementing mitigation projects in Sweet Home is addressed in Chapter 5 (Plan Adoption, Maintenance and Implementation). Although benefit-cost analysis is a powerful tool for helping to evaluate and prioritize mitigation projects, and a requirement for all FEMA hazard mitigation grants, benefit-cost analysis should not be considered the sole determinant for mitigation actions. In some cases, the potential for negative effects from a particular natural hazard may simply be deemed unacceptable, such as the potential for deaths and injuries, and thus mitigation may be undertaken without benefit-cost analysis. 1 See FEMA webpage for current values of life and injuries as they are periodically recalculated. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A2-4

184 APPENDIX 3: COMMUNITY INVOLVEMENT DOCUMENTATION General Plan Update Meeting Documents... 2 March 5 th, March 18 th, & April 8 th 2014 Update Meeting PowerPoint... 2 March 18, 2014 Plan Update Meeting Documents...26 March 18, 2014 Meeting Agenda...26 March 18, 2014 Meeting Minutes...27 April 8, 2014 Plan Update Meeting Documents April 8, 2014 Meeting Agenda...29 April 8, 2014 Meeting Minutes...30 April 14, May 4, 2015 Plan Review Period Documents Regional Hazard Mitigation Contact List...32 Request for Comments Plan Review Webpage...35 City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A3-1

185 Sweet Home Multi-Hazard Mitigation Plan 2014 Update Kick-Off and Work Session Agenda March 5 th, March 18 th, and April 8 th 2014 Review of the hazards potentially impacting Sweet Home (SHMP Chapters 1, 6-15). An overview of hazard mitigation planning (SHMP Chapter 1). Review of the SHMP Goals (SHMP Chapter 4). Discussion of potential mitigation projects to address the identified problems (SHMP Chapter 4). Why is the City Updating its Mitigation Plan? To remain eligible for a variety of grant programs, FEMA requires an updated and approved plan every five years. Things change. New structures are built, vulnerabilities and exposure to hazards change, community values and reliance on infrastructure change, and hence the levels of acceptable risk change. Note: The Sweet Home Multi-Hazard Mitigation Plan is also known as the Sweet Home Mitigation Plan or SHMP. TCL PLANNING CONSULTANTS Sweet Home, Oregon 1 March/April 2014

186 Sweet Home Mitigation Plan 2014 Update Sweet Home Area Potential Hazards Natural Technological Human-Caused Floods Winter Storms Landslides Wildland/Urban Interface Fires Earthquakes Volcanic Hazards Dam Failure Disruption of Utility & Transportation Systems Hazardous Materials Terrorism See Page 9 in Chapter 1 for a brief description of Hazards impacting Sweet Home. Chapters 6-15 provide in depth descriptions of each of these ten Hazards, and several have maps (pages 6-3, 6-7, 8-5, and 9-2). The first six listed hazards may be primarily natural, but the first four could also have anthropogenic factors, local (e.g., fire) or global. TCL PLANNING CONSULTANTS Sweet Home, Oregon 2 March/April 2014

187 (Source: TCL/K. Goettel) Sweet Home Mitigation Plan 2014 Update Risk is the Combination of the Threat or Hazard Event and Vulnerability or Exposure TCL PLANNING CONSULTANTS Sweet Home, Oregon 3 March/April 2014

188 Sweet Home Mitigation Plan 2014 Update Threat or Hazard Event Threat or Hazard Event refers to natural or human-caused events that may cause damages, losses or casualties. Hazards are characterized by their frequency and severity as well as by the duration, speed of onset and the geographic area affected. Examples of threats or hazard events include floods, winter storms, landslides, failures of critical systems and facilities, earthquakes, hazardous material spills, human violence, and terrorism. A hazard event, by itself, may not result in any negative impacts on a community. Threat or hazard events do not produce risk to people and property, unless there is vulnerable inventory exposed to the hazard. Risk to people, buildings and/or infrastructure results only when hazards are combined with vulnerability or exposure. TCL PLANNING CONSULTANTS Sweet Home, Oregon 4 March/April 2014

189 Sweet Home Mitigation Plan 2014 Update Vulnerability and Exposure (essentially synonymous terms for our purposes) Vulnerability is the degree to which individuals, the community as a whole, the built environment, systems, other assets and resources, and cultural, economic, and social activity are susceptible to harm, degradation, or destruction. Exposure is the quantity, value and vulnerability of the built environment (inventory of people, buildings and infrastructure) in a particular location subject to one or more hazards. Vulnerability involves the inventory of people and the built environment in harm s way. Inventory can be characterized by the number, size, type, use, and occupancy of buildings as well as by the infrastructure present in any given specific location. Infrastructure includes bridges, roads and other transportation systems, utilities (e.g., potable water, wastewater, natural gas, and electric power), telecommunications systems, and so on. Critical facilities and critical infrastructure, are especially important to a community, particularly during emergency situations. Critical facilities include police and fire stations, hospitals, 911 centers, emergency operations centers, and emergency shelters. Critical infrastructure include important utility links, utility lines, and life lines, that are essential in providing service to large numbers of people such as potable water, waste water sanitation, electricity, natural gas, and so on. TCL PLANNING CONSULTANTS Sweet Home, Oregon 5 March/April 2014

190 Sweet Home Mitigation Plan 2014 Update Risk Risk is the threat to people and the built environment: the potential for damages, losses and casualties arising from hazards. Risk is the Combination of the Threat or Hazard Event and Vulnerability or Exposure. The level of risk at a given location, building, facility or infrastructure depends on the combination of threat or hazard event and vulnerability. A disaster event happens when a hazard event is combined with vulnerable inventory -- when a hazard event strikes vulnerability inventory exposed to the hazard. For example, nonelevated critical infrastructure and facilities located in areas that frequently exposed to high flood waters. The highest risk in a community occurs in high hazard areas (frequent and/or severe hazard events) with large inventories of vulnerable buildings or infrastructure. However, high risk can also occur with only moderately high hazard, if there is a large inventory of highly vulnerable inventory exposed to the hazard. This could include seismically unsound buildings (e.g., schools, hospitals) exposed to severe earthquakes infrequently. Conversely, a high hazard area can have relatively low risk if the inventory is resistant to damages (e.g., elevated to protect against flooding or strengthened to minimize earthquake damages). TCL PLANNING CONSULTANTS Sweet Home, Oregon 6 March/April 2014

191 Sweet Home Mitigation Plan 2014 Update Mitigation Planning Mitigation: The key element for all hazard mitigation projects is that they reduce risk. Mitigation actions reduce the potential for damages, losses, and casualties in future disaster events. Repair of buildings or infrastructure damaged in a disaster is not mitigation because repair simply restores a facility to its pre-disaster condition and does not reduce the potential for future damages, losses, or casualties. Hazard mitigation projects may be initiated proactively (before a disaster), or after a disaster has already occurred. In either case, the objective of mitigation is always is to reduce future damages, losses or casualties. The benefits of a mitigation project are the reduction in risk (i.e., the avoided damages, losses, and casualties attributable to the mitigation project). In other words, benefits are simply the difference in expected damages, losses, and casualties before mitigation (as-is conditions) and after mitigation. Key Questions: (1) Are the levels of risk and potential loss acceptable in a given situation? (2) Is a given situation worth mitigating? This consideration, at least when requesting FEMA grants, requires cost/benefit analysis (see Section 1.6 in Chapter 1 and Appendix 2 for details). TCL PLANNING CONSULTANTS Sweet Home, Oregon 7 March/April 2014

192 Hazard Flood Winter Storms Earthquakes Landslides Wildland/Urban Interface Fires General Sweet Home Mitigation Plan 2014 Update Examples of Common Mitigation Projects (Source: K. Goettel) Mitigation Project Build or improve levees or flood walls Improve channels for flood control Improve drainage systems and culvert capacities Create detention ponds for storage Relocate, elevate or floodproof flood-prone structures Acquire and demolish highly flood-prone structures Add emergency generators for critical facilities Improve redundancy of utility systems Trim trees to reduce failures of utility lines Upgrade seismic performance of buildings Upgrade seismic performance of infrastructure Remediate slide conditions Relocate utility lines or structures Increase fire safe construction practices Vegetation (fuel load) control Enhance emergency planning and mutual aid Expand public education programs TCL PLANNING CONSULTANTS Sweet Home, Oregon 8 March/April 2014

193 Sweet Home Mitigation Plan 2014 Update Four-Step Mitigation Planning Framework Mission Statement: The Mission Statement states the purpose and defines the primary function of the Sweet Home Hazard Mitigation Plan. The Mission Statement is an actionoriented summary that answers the question Why develop a hazard mitigation plan? Goals: Goals identify priorities and specify how Sweet Home intends to work toward reducing the risks from natural and human-caused hazards. The Goals represent the guiding principles toward which the community s efforts are directed. Goals provide focus for the more specific issues, recommendations and actions addressed in Objectives and Action Items. Objectives: Each Goal has Objectives which specify the directions, methods, processes, or steps necessary to accomplish the plan s Goals. Objectives then lead directly to specific Action Items. Action Items: Action items are specific well-defined activities or projects that work to reduce risk. The Action Items represent the steps necessary to achieve the Mission Statement, Goals and Objectives. SHMP Mission Statement Proactively facilitate and support community-wide policies, practices, and programs that make Sweet Home more disaster resistant and disaster resilient. (For details see Chapter 4, Sections 4.2 & 4.3.) TCL PLANNING CONSULTANTS Sweet Home, Oregon 9 March/April 2014

194 Sweet Home Mitigation Plan 2014 Update SHMP Goals Goal 1: Reduce the Threat to Life Safety Objectives: A. Enhance life safety by minimizing the potential for deaths and injuries in future disaster events. B. Enhance life safety by improving public awareness of earthquakes and other natural hazards posing life safety risk to the Sweet Home community. Goal 2: Reduce the Threats to City s Buildings, Facilities and Infrastructure Objectives: A. Identify buildings and infrastructure at high risk from one or more hazards. B. Conduct risk assessments for critical buildings, facilities and infrastructure at high risk to determine cost effective mitigation actions to eliminate or reduce risk. C. Implement mitigation measures for buildings, facilities and infrastructure which pose an unacceptable level of risk. D. Ensure that new buildings and infrastructure in Sweet Home are adequately designed and located to minimize damages in future disaster events. (See Chapter 4.) TCL PLANNING CONSULTANTS Sweet Home, Oregon 10 March/April 2014

195 Sweet Home Mitigation Plan 2014 Update Goal 3: Enhance Emergency Response Capability, Emergency Planning and Post-Disaster Recovery Objectives: A. Ensure that critical facilities and critical infrastructure are capable of withstanding disaster events with minimal damages and loss of function. B. Enhance emergency planning to facilitate effective response and recovery from future disaster events. C. Increase collaboration and coordination between Sweet Home, nearby communities, utilities, businesses and citizens to ensure the availability of adequate emergency and essential services for the Sweet Home community during and after disaster events. Goal 4: Vigorously Seek Funding Sources for Mitigation Actions Objectives: A. Prioritize and fund action items with the specific objective of maximizing mitigation, response and recovery resources. B. Explore both public (local, state and federal) funding and private sources for mitigation actions. (See Chapter 4.) TCL PLANNING CONSULTANTS Sweet Home, Oregon 11 March/April 2014

196 Sweet Home Mitigation Plan 2014 Update Goal 5: Increase Public Awareness of Natural Hazards and Enhance Education and Outreach Efforts Objectives: A. Develop and implement education and outreach programs to increase public awareness of the risks from natural hazards B. Provide information on resources, tools, partnership opportunities and funding resource sources to assist the community in implementing mitigation activities. C. Strengthen communication and coordinate participation among and within public agencies, non-profit organizations, business, industry and the public to encourage and facilitate mitigation actions. Goal 6: Incorporate Mitigation Planning into Natural Resource Management and Land Use Planning Objectives: A. Protect Sweet Home s sources of potable water. B. Balance natural resource management, land use planning, and natural hazard mitigation to protect life, property and the environment. C. Preserve, rehabilitate, and enhance environmentally sensitive areas and natural systems within Sweet Home to both enhance habitats and serve natural hazard mitigation functions. (See Chapter 4.) TCL PLANNING CONSULTANTS Sweet Home, Oregon 12 March/April 2014

197 OG OG OG OG OG OG 1-2 yrs OG 1-2 yrs OG 1-2 yrs Coordinating Organizations Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning ST #1 ST #2 ST #3 ST #4 ST #5 ST #6 LT #1 LT #2 LT #3 LT #4 LT #5 Sweet Home Mitigation Plan 2014 Update Table 4-2: Multi-Hazard Mitigation Action Items (SHMP: Chapter 4, page 4-6) Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Multi-Hazard Mitigation Action Items Develop detailed inventories of at-risk buildings & infrastructure and refine priorities for mitigation actions. Identify and pursue funding opportunities to implement mitigation actions. Create and/or empower existing neighborhood groups to help their close neighbors during hazard emergencies and notify emergency response officials if medical assistance is needed. Work with Linn County Shelter Committee (LCM), including Red Cross, to continually update Emergency Shelter Plans for the Sweet Home community. Include assessing needs especially for vulnerable populations (e.g., needs for generators in shelters). Create Personal Preparedness program for Sweet Home residents. Develop public & private sector partnerships to foster hazard mitigation activities. Integrate hazard, vulnerability and risk Mitigation Plan findings into enhanced Emergency Operations planning. Continue the formal role for the SHMPC to maintain a sustainable process to encourage, implement, monitor, & evaluate city-wide mitigation actions. Develop education programs aimed at mitigating the risk posed by hazards. Integrate the Mitigation Plan findings into planning and regulatory documents and programs. Create a local information network for emergencies including (1) mapping neighborhoods, and (2) emergency number magnets/shopping bags. City staff City & Fire District staff SHMPC City; LCM; SHMPC SHMPC SHMPC EMC SHMPC SHMPC SHMPC SHMPC Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Multi-Hazard Mitigation Action Items G-1 G-2 G-3 G-4 G-5 G-6 TCL PLANNING CONSULTANTS Sweet Home, Oregon 13 March/April 2014

198 OG OG Yrs Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update Table 4-3: Flood Mitigation Action Items (Chapter 4, Page 4-7) Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department Coordinating Organizations Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Flood Mitigation Action Items Flood Mitigation Action Items: Within FEMA-Mapped Floodplains ST #1 Begin process of code revisions for storage in floodplains. City: Community Development X X LT #1 LT #2 Survey elevation data for structures within the 100-yr floodplain, including coordination with Linn County Planning on use of LIDAR imaging for elevation information. For structures within the 100-year floodplain and especially for structures deep in the floodplain, explore mitigation options with property owners. Flood Mitigation Action Items: Outside FEMA-Mapped Floodplains City: Building, Planning, Engineering staff SHMPC X X X X ST #1 Complete the inventory and mapping of locations in sweet Home subject to frequent storm water flooding. City: Public Works X LT #1 For locations with repetitive flooding and significant damages or road closures, determine and implement. City: Public Works X X X Duplicated as Table 6-2 in Chapter 6, page 6-14 G-1 G-2 G-3 G-4 G-5 G-6 TCL PLANNING CONSULTANTS Sweet Home, Oregon 14 March/April 2014

199 OG OG OG OG OG Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update Table 4-4: Winter Storm Mitigation Action Items (Chapter 4, page 4-8) Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; LCM = Linn County Shelter Committee xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Winter Storm Mitigation Action Items Coordinating Organization s Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 ST #1 Assess need for back up power generators for emergency shelters in SH. SHMPC; LCM X X ST #2 LT #1 LT #2 LT #3 LT #4 Identify critical need locations, vulnerable populations, and vulnerable independent individuals. Consider upgrading lines & poles to improve wind/ice loading, undergrounding critical lines, and adding interconnect switches to allow alternative feed paths and disconnect switches to minimize outage areas. Encourage Pacific Power (PPL) to prioritize a coordinated emergency response (including enhanced communications) with City Public Works. Assess needs for back up power generators for all City-owned designated critical facilities and ensure that the highest priority critical facilities have generators or are wired to accept plug-in generators, as has been done for the waste water treatment plant (generator) and the new water treatment plant (wiring set up). Include assessing generator needs for City Hall and the Community Center. Enhance tree trimming efforts especially for transmission lines and trunk distribution lines. City; SHFAD; Linn Co. Electrical Utility (PPL) City; PPL City PPL; CTC X X X X X X X X X X X X X X X ST #5 Continue City-wide efforts encouraging property owners to keep trees trimmed near their electrical service drops. SHMPC; CTC X X X X Duplicated as Table 7-5 in Chapter 7, page 7-9. G-1 G-2 G-3 G-4 G-5 G-6 TCL PLANNING CONSULTANTS Sweet Home, Oregon 15 March/April 2014

200 OG OG 1-2 yrs Coordinating Organizations Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update Table 4-5: Landslide Mitigation Action Items (Chapter 4, page 4-9) Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Landslide Mitigation Action Items ST #1 Implementation of geo-tech work for new construction in previously identified areas subject to land slide. SHMPC; CPWD; CCDD X X X X LT #1 Consider landslide mitigation actions for slides seriously threatening buildings or infrastructure. SHMPC; CPWD X X X LT #2 Limit future development in high landslide potential areas. CCDD X X X X X X Duplicated as Table 8-2 in Chapter 8, page 8-7. G-1 G-2 G-3 G-4 G-5 G-6 TCL PLANNING CONSULTANTS Sweet Home, Oregon 16 March/April 2014

201 OG OG OG Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update Table 4-6: Wildland/Urban Interface Mitigation Action Items (Chapter 4, page 4-10) ST #1 LT #1 Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Wildland/Urban Interface Mitigation Action Items Identify and map evacuation routes and procedures for high risk areas, disseminate and educate the public. Encourage fire-safe construction practices for existing and new construction in high risk areas. Coordinating Organizations CE; SHPD SHMPC; CCDD Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 X X X X X X X X LT #2 Continue fuels reduction projects and public education for the high hazard areas of SH identified previously. Initial work has been done, but continuing efforts necessary since fuels grow back. SHFAD X X X X Duplicated as Table 9-8 in Chapter 9, page G-1 G-2 G-3 G-4 G-5 G-6 TCL PLANNING CONSULTANTS Sweet Home, Oregon 17 March/April 2014

202 OG 10 Yrs OG OG OG Coordinating Organizations Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update Table 4-7: Earthquake Mitigation Action Items (Chapter 4, page 4-11) ST #1 ST #2 ST #3 LT #1 LT #2 Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Earthquake Mitigation Action Items (1a) Complete inventory of important buildings, including schools, that may be particularly vulnerable to earthquake damage using FEMA s Rapid Visual Screening, (1b) and, as needed and as funding is available, conduct more detailed seismic vulnerability analysis of buildings which appear particularly vulnerable [*may require technical assistance from consultants]. Complete inventory of residential and commercial buildings that may be particularly vulnerable to earthquake damage, including pre-1940s homes, unreinforced masonry buildings, tilt-up buildings and buildings with soft first stories. [*May require technical assistance from consultants, and additional funding.] Obtain and make available to the public FEMA pamphlets to educate building owners and residents about structural and non-structural retrofitting of vulnerable homes and encourage retrofits. Seek funding to retrofit important public facilities with significant seismic vulnerabilities. Same as ST#4 in Table 4-2, and ST#1 and LT#3 in Table 4-4. (Addresses Critical Facilities and Emergency Shelters.) City Staff* City Staff* AHMPC City Same Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 X X X X X X X X X X X X X Duplicated as Table 10-6 in Chapter 10, page G-1 G-2 G-3 G-4 G-5 G-6 TCL PLANNING CONSULTANTS Sweet Home, Oregon 18 March/April 2014

203 1-2 Yrs Coordinating Organizations Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Capability Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update Table 4-8: Volcanic Hazards Mitigation Action Items (Chapter 4, page 4-12) Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Volcanic Hazards Mitigation Action Items ST #1 Evaluate capability of the new water treatment plant to deal with high turbidity from ash falls and upgrade emergency response plan to deal with ash falls. CPWD X X Duplicated as Table 11-4 in Chapter 11, page G-1 G-2 G-3 G-4 G-5 G-6 TCL PLANNING CONSULTANTS Sweet Home, Oregon 19 March/April 2014

204 OG 1-2 Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update Table 4-9: Dam Failure Mitigation Action Items (Chapter 4, page 4-12) ST #1 ST #2 Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Dam Failure Mitigation Action Items Obtain high resolution maps of dam failure inundation areas and update emergency response plan. Encourage US Corps of Engineers to complete seismic vulnerability assessments for Green Peter and Foster dams & make seismic improvements as necessary. Coordinating Organizations US Corps of Engineers; City City Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 X X X X X X Duplicated as Table 12-7 in Chapter 12, page G-1 G-2 G-3 G-4 G-5 G-6 TCL PLANNING CONSULTANTS Sweet Home, Oregon 20 March/April 2014

205 OG 5 Yrs 5 Yrs 5 Yrs OG Coordinating Organizations Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update ST #1 LT #1a LT #1b LT #2 LT #3 Table 4-10: Utility and Transportation System Disruption Mitigation Action Items (Chapter 4, page 4-13) Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CTC = City Tree Commission; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; ODF = OR Dept. of Forestry; CE = City Engineering; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Utility and Transportation System Disruption Mitigation Action Items Same as ST#4 in Table 4-2, and ST#1 and LT#3 in Table 4-4. (Addresses Critical Facilities and Emergency Shelters.) Create an emergency potable water filling station. Obtain/have available a portable potable water source (e.g., tank truck, tender) for emergency water deliveries. Have a list of contact information and establish procedures for enhancing communications with and engaging the services of the Amateur Radio Emergency Services (ARES) in SH. Educate and encourage residents to maintain several days of emergency supplies for power outages or road closures. Same CPWD CPWD City; Linn Co. Emergency Services; ARES SHMPC Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 X X X X X X X X X X X X X X X X X X Duplicated as Table 13-3 in Chapter 13 page G-1 G-2 G-3 G-4 G-5 G-6 TCL PLANNING CONSULTANTS Sweet Home, Oregon 21 March/April 2014

206 OG OG Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update Table 4-11: Hazmat Incident Mitigation Action Items (Chapter 4, page 4-14) LT #1 LT #2 Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Hazmat Incident Mitigation Action Items Building on previous work, update site-specific knowledge of hazardous chemical inventories in SH including the State Fire Marshal s Community Right to Know lists so that first responders have readily available current information when needed. Enhance emergency planning, agency coordination, emergency response training and equipment to address hazardous materials incidents. Coordinating Organizations SHAFD; SHPD SHAFD; SHPD Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 Duplicated as Table 14-7 in Chapter 14, page G-1 G-2 G-3 G-4 G-5 G-6 X X X X TCL PLANNING CONSULTANTS Sweet Home, Oregon 22 March/April 2014

207 OG OG Timeline Reduce Threats to Life / Safety Reduce Threats to Built - Environment Emergency Response Seek Funding Public Awareness Integrate Mitigation Planning Sweet Home Mitigation Plan 2014 Update Table 4-12: Terrorism Incident Mitigation Action Items (Chapter 4, page 4-14) LT #1 LT #2 Abbreviations: ST = Short Term; LT = Long Term; SH = Sweet Home; Yrs = Years; OG = Ongoing; EMC = Emergency Management Committee; CFs = Critical Facilities; SHMPC = Sweet Home Mitigation Planning Committee; CPWD = City Public Works Department; CCDD = City Community Development Department; SHFAD = SH Fire & Ambulance District; SHPD = SH Police Department xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Terrorism Mitigation Action Items Building on previous work, maintain enhanced emergency planning, agency coordination, emergency response training and equipment to address terrorism incidents. At City-owned and/or operated critical facilities, limit accessibility (e.g., fencing, walls) to (1) sensitive systems (e.g., HVAC) and (2) sensitive parts. Encourage School District to do likewise. [City has previously made considerable progress on its CFs.] Coordinating Organizations SHPD CPWD; City; School District Mitigation Plan Goals Addressed G-1 G-2 G-3 G-4 G-5 G-6 Duplicated as Table 15-3 in Chapter 15, page G-1 G-2 G-3 G-4 G-5 G-6 X X X X TCL PLANNING CONSULTANTS Sweet Home, Oregon 23 March/April 2014

208 Duplicated in Sweet Home s 2012 Emergency Operations Plan as Table 2-3 on page 2-6. Sweet Home Mitigation Plan 2014 Update SWEET HOME AREA 2003 ALL HAZARD ANALYSIS MATRIX (Sorted by Total Risk) (Source: TCL Planning Consultants/Sweet Home City Staff Work Session December 2003) MAJOR HAZARD EVENT HISTORY (WF = 2) (Max Score = 20) VULNERABILITY (WF = 5) (Max Score = 50) MAXIMUM THREAT (WF = 10) (Max Score = 100) PROBABILITY (WF = 7) (Max Score = 70) TOTAL RISK (Max Score = 240) Severe Weather/Winter Storm Utility Failures (e.g., Electricity, Natural Gas, Communications) Water Supply Emergencies Flooding Earthquake Drought Wildland/Urban Interface Fire Hazardous Materials Emergency (HAZMAT) Infrastructure Failures (e.g., Bridge, Treatment Plant, Building Collapse) Volcano Eruption Epidemiological Event Dam Failure Urban Fire Transportation Accidents Weapon of Mass Destruction (WMD) Work/School Violence Terrorism Landslide Civil Disturbance Secondary Effects of Major Hazard Event in Region TCL PLANNING CONSULTANTS Sweet Home, Oregon 24 March/April 2014

209 CITY OF SWEET HOME SPECIAL CITY COUNCIL MEETING AGENDA March 18, :00 p.m. Sweet Home Police Services Building Training Room 1950 Main Street Sweet Home, OR Call to Order 2. Roll Call: CITY COUNCIL Councilor Angulo Councilor Fentiman Mayor Gourley Councilor Hobbs Councilor Mahler Councilor McKee Councilor Trask PLANNING COMMISSION James Goble Lance Gatchell Anay Hausner Eva Jurney Greg Stephens Henry Wolthuis Vacant ALL HAZARD MITIGATION PLANNING COMMITTEE Ned Kilpatrick Scott LaRoque Stephen Young 3. A Joint Work Session for the purpose of reviewing the All Hazard Mitigation Plan and taking public comment. 4. Adjournment

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212 SPECIAL CITY COUNCIL MEETING AGENDA April 8, :00 p.m. Sweet Home City Hall/Council Chambers th Avenue Sweet Home, OR Call to Order 2. Roll Call: CITY COUNCIL Councilor Angulo Councilor Fentiman Mayor Gourley Councilor Hobbs Councilor Mahler Councilor McKee Councilor Trask PLANNING COMMISSION James Goble Lance Gatchell Anay Hausner Eva Jurney Greg Stephens Henry Wolthuis Ned Kilpatrick ALL HAZARD MITIGATION PLANNING COMMITTEE Ned Kilpatrick Scott LaRoque Stephen Young 3. A Joint Work Session for the purpose of reviewing the All Hazard Mitigation Plan and taking public comment. 4. Adjournment

213 CITY OF SWEET HOME SPECIAL MEETING CITY COUNCIL WORK SESSION MINUTES April 8, 2014 The Special City Council Joint Work Session opened at 6:00 p.m. in the City Council Chambers. Roll Call: Councilor Angulo A Councilor Mahler P Councilor Fentiman P Councilor McKee P Mayor Gourley P (6:04 p.m.) Councilor Trask P Councilor Hobbs P PLANNING COMMISSION James Goble P Greg Stephens A Lance Gatchell P (6:25 p.m.) Henry Wolthuis P Anay Hausner A Ned Kilpatrick P Eva Jurney A ALL HAZARD MITIGATION PLANNING COMMITTEE Ned Kilpatrick P Fire Chief M. Beaver A Scott LaRoque A Police Chief J. Lynn P Stephen Young A Public Works Director M. Adams P Vacant City Manager C. Martin P Other: Recording Secretary Wendy Younger, Terry & Carol Lewis, TCL Planning Consultants, and Planning Assistant Julie Fisher Registered Visitors: None Media: None The purpose of the Special City Council Joint Work Session was to have the City Council, Planning Commission and All Hazard Mitigation Planning Committee continue the process of reviewing and making updates to the Sweet Home Hazard Mitigation Plan. City Manager Craig Martin gave some updates on items from the last meeting including activation thresholds for emergency response and the United States Army Corps of Army Engineers revised Dam Failure Flood Maps. Terry Lewis, TCL Planning Consultants, reviewed a PowerPoint handout starting on page 16 of the handout and the group reviewed, asked questions, and made updates as needed to Tables 4-5 Landslide Mitigation Action Items; Table 4-6: Wild land/urban Interface Mitigation Action Items; Table 4-7 Earthquake Mitigation Action Items; 4-8 Volcanic Hazards Mitigation Action Items; 4-9 Dam Failure Mitigation Action Items; 4-10 Utility and Transportation System Disruption Mitigation Action Items; 4-11 Hazmat Incident Mitigation Action Items; 4-12 Terrorism Incident Mitigation Action Items. Carol Lewis documented the updates/changes to the action items as they were made.

214 Page 2 Special City Council Meeting Minutes April 8, 2014 Terry Lewis stated that updates to the Sweet Home Hazard Mitigation Plan would be made and the updated draft would be posted on the City s website for review. The official draft document will go before the City Council for adoption along with a resolution in May and then the final approved document would be sent to FEMA. Adjournment: The meeting adjourned at 7:07 p.m. Approved by Council 4/22/14

215 Regional Hazard Mitigation Contact List Name Affiliation Address Address Jared Cornell Albany and Eastern Railroad 110 Industrial Way, Lebanon, OR Kim Titus Bureau of Land Management 1717 Fabry Rd. SE, Salem, Oregon Dave Furtwangler Cascade Timber Consulting 3210 US-20, Sweet Home, OR Scott McDowell City of Brownsville, City Administrator P.O. Box 189, Brownsville, OR Ronda Fischer City of Halsey, City Administrator P.O. Box 10 Halsey, OR Gary Marks City of Lebanon, City Manager 924 Main Street Lebanon, Oregon Walt Wendolowski City of Lebanon, Community Development Director 925 Main Street Lebanon, Oregon Ron Whitlatch City of Lebanon, Engineering Manager 927 Main Street Lebanon, Oregon Dan Woodson City of Lebanon, Fire Chief 926 Main Street Lebanon, Oregon Stacie Cook City of Mill City, City Recorder 444 S 1st Avenue Mill City, OR scook@ci.mill-city.or.us Barbara Castillo City of Millersburg, City Administrator 4222 NE Old Salem Road, Albany, OR bcastillo@cityofmillersburg.org Ginger Griffith City of Scio PO Box 37 Scio, OR sciocitymgr@smt-net.com Judy Smith City of Sodaville, City Administrator Sodaville Road, Lebanon, OR sodaville@centurytel.net Craig Martin City of Sweet Home, City Manager th Avenue, Sweet Home, OR cmartin@ci.sweet-home.or.us Mike Adams City of Sweet Home, Public Works Director th Avenue, Sweet Home, OR madams@ci.sweet-home.or.us Joe Graybill City of Sweet Home, Engineer th Avenue, Sweet Home, OR jgraybill@ci.sweet-home.or.us Mike Remesnik City of Sweet Home, Building Inspector th Avenue, Sweet Home, OR mremesnik@ci.sweet-home.or.us Pat Wood City of Sweet Home, Maintenance Superintendent th Avenue, Sweet Home, OR pwood@ci.sweet-home.or.us Georgia Edwards City of Tangent, City Administrator P.O. Box 251, Tangent, OR georgia@cityoftangent.org Catherine Nelson City of Waterloo, City Administrator P.O. Box 1066, Lebanon, OR cityofwaterloo@centurytel.net Ian Madin Department of Geology and Mineral Industries 800 NE Oregon Street, Suite 965, Portland, OR ian.madin@dogami.state.or.us Christine Shirley Department of Land Conservation and Development's Natural Hazards Program 635 Capitol St. NE, Suite 150, Salem christine.shirley@state.or.us Joe Larsen Linn County Emergency Management Agency, Coordinator 1115 Jackson St. SE, Albany, OR jlarsen@linnsheriff.org Alyssa Boles Linn County Planning and Building, Assistant Planner 301 SW 4th Ave., Albany, OR aboles@co.linn.or.us Olivia Glantz Linn County Planning and Building, Associate Planner 302 SW 4th Ave., Albany, OR oglantz@co.linn.or.us City of Sweet Home August 2015 Sweet Home Mitigation Plan

216 Tony West Linn County Planning and Building, Building Official 303 SW 4th Ave., Albany, OR Robert Wheeldon Linn County Planning and Building, Director 300 SW 4th Ave., Albany, OR Darrin Lane Linn County Road Department 3010 Ferry St SW, Albany, OR Bruce Riley Linn County Sheriff's Office, Sheriff 1116 Jackson St. SE, Albany, OR Jim Yon Linn County Sheriff's Office, Undersheriff 1116 Jackson St. SE, Albany, OR Debra Paul Linn Soil & Water Conservation District, Office Administrator Hwy 99E Suite C Tangent, Oregon linn.swcd@oacd.org Dennis Sigrist Office of Emergency Management 3225 State Street, Salem OR dsigrist@oem.state.or.us Fred Abousleman Oregon Cascades West Council of Governments 1400 Queen Ave SE Ste 201 Albany, OR fabousle@ocwcog.org Nancy Taylor Oregon Department of Fish and Wildlife 4034 Fairview Industrial Drive SE, Salem, OR nancy.c.taylor@state.or.us Craig Pettinger Oregon Department of Forestry 4691 HWY 20, Sweet Home, OR cpettinger@odf.state.or.us Dana Field Oregon Department of State Lands 775 Summer St. NE Suite 100, Salem, OR dana.field@dsl.state.or.us Amy Ramsdell Oregon Department of Transportation 3701 SW Philomath Boulevard, Corvallis, OR Amy.j.ramsdell@odot.state.or.us Prescott Mann Oregon Department of Transportation - Rail Division th Street N.E., Suite 3, Salem, Oregon prescott.e.mann@odot.state.or.us Tia Morehouse Red Cross Mid-Valley District 3388 SW Pacific Blvd., Albany, OR tia.morehouse@redcross.org Eric Andersen South Santiam Watershed Council 4431 Highway 20, Sweet Home, OR monitoring.coordinator@gmail.com Dave Barringer Sweet Home Fire & Ambulance District 1099 Long St, Sweet Home, OR dbarringer@sweethomefire.org Jeff Lynn Sweet Home Police Department 1951 Main Street, Sweet Home, OR jlynn@ci.sweet-home.or.us Keith Winslow Sweet Home School District 1920 Long Street Sweet Home, OR keith.winslow@sweethome.k12.or.us Jeremy Totman T Wiley Creek Drive, Sweet Home, OR jeremy@t2incorporated.com Chris Martin Ti Squared Technologies 1305 Clark Mill Rd Sweet Home, OR cmartin@tisquaredtech.com Christie Johnson U.S. Army Corps of Engineers PO Box 807, Foster, OR Christie.L.Johnson@usace.army.mil Cindy Glick U.S. Forest District Sweet Home Ranger District 4431 Highway 20, Sweet Home, OR cglick@fs.fed.us Water and Wastewater Treatment, CH2M Hill, Scott LaRoque Project Manager P.O. Box 750 Sweet Home, OR Scott.Laroque@CH2M.com Andreas Villegas Weyerhaeuser Foster Veneer, Plant Manager 6011 US-20 Sweet Home, OR andresvillegas@weyerhaeuser.com City of Sweet Home August 2015 Sweet Home Mitigation Plan

217 Request for Comments Message 2015 Draft Multi-Hazard Mitigation Plan (SHMP) Open Public Review and Comment. All comments must be received by May 4th. The City of Sweet Home is pleased to submit the Draft 2015 Sweet Home Hazard Mitigation Plan (SHMP) for open public review and comment. The SHMP can be viewed via the following link or visiting the City of Sweet Home s website at The SHMP represents the City s primary hazard mitigation guidance document, and provides an updated and comprehensive description of Sweet Home s historical and current hazard analysis, mitigation strategies, goals and objectives. The SHMP defines a long-term strategy for reducing the impact of disasters by supporting protection and prevention activities, easing response, and speeding recovery to create better prepared and more resilient community. All state and local agencies are required to have a Federal Emergency Management Agency (FEMA) approved multi-hazard mitigation plan to be eligible for disaster mitigation grant assistance. The SHMP not only fulfills this requirement, but also provides direction and guidance on implementation of hazard mitigation by state agencies, local governments, tribal governments, and the private sector. The SHMP must be reviewed, updated and submitted to FEMA for approval at least once every five years in order to maintain eligibility for FEMA grant programs. The City of Sweet Home has lead responsibility for the development and maintenance of the SHMP, but the preparation of the 2015 SHMP is truly a collaborative partnership with numerous stakeholders from local, state and federal government agencies, private sector organizations, and residents of Sweet Home. Your time and participation in assisting to build long-term personal and community resilience and sustainability in Sweet Home is greatly appreciated. Public Comment Instructions The City of Sweet Home is requesting either general or specific comments on the 2015 Draft Sweet Home Hazard Mitigation Plan. Written comments may also be submitted to: Laura LaRoque via at llaroque@ci.sweet-home.or.us or U.S. mail at the address listed below. Please provide the exact chapter, section, and page number for ease of editorial reference along with your name, address and daytime telephone number. The SHMP can be viewed via the following link or visiting the City of Sweet Home s website at All comments must be received by May 4th. City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A3-34

218 PLAN REVIEW WEBPAGE City of Sweet Home August 2015 Sweet Home Mitigation Plan Page A3-35