DRAFT Sacramento s Comprehensive Flood Risk Reduction Program

Transcription

1 DRAFT Sacramento s Comprehensive Flood Risk Reduction Program March 20, th St, 7 th Floor Sacramento, CA 95814

2 Table of Contents 1. Introduction Flood System Management... 6 American and Sacramento Rivers and Tributaries... 6 Operations and Maintenance... 7 Levee Security Land Use Growth Management Urban Levee Zoning Refuge Areas Hazard Mitigation Emergency Management Flood Preparedness Flood Warning Emergency Response Risk Communication National Flood Insurance Program Planned Outcomes References Appendix A: Table of Authorizations Figures Figure 1: Regional Location... 4 Figure 2: Sacramento Area - Elements of Flood and Residual Risk Management... 5 Figure 3: SAFCA 200-year Flood Management Projects Figure 4: SAFCA 500-year Flood Management Projects Figure 5: Sacramento River 500-year Flood Profile Tables Table 1: Structural Flood Management Projects... 8 Sacramento s Comprehensive Flood Risk Reduction Program 1

3 The City of Sacramento has grown at the confluence of the American and Sacramento rivers, enjoying the benefits of the Sacramento River Flood Control Project s (SRFCP s) levees and bypasses as well as the headwater dams that have been added to the project. Sacramento is the largest city protected by this flood control system. The Sacramento Area Flood Control Agency (SAFCA), in partnership with state, federal and local agencies, is implementing a comprehensive flood risk management program for the Sacramento area. The program combines structural improvements protecting the area from floods up to the 500-year event with management of the residual risk of flooding through non-structural measures being planned and implemented by the City of Sacramento and the County of Sacramento and other partners. 1. INTRODUCTION Sacramento is regarded as having the second highest flood risk among major cities in the nation, below only New Orleans. This high risk is a result of the historic settling of the community at the transportation crossroads then offered by the American and Sacramento rivers. Now the state capital of the sixth-largest economy in the world, Sacramento has grown up around these rivers even as the transcontinental railroad, Interstate highways, and Sacramento International Airport have overshadowed the rivers as transportation modes (Figure 1). Following severe floods and decades of planning, in the early 1900s the federal and state governments began constructing the SRFCP, which combined areas where the major rivers were confined between levees with weirs that allowed high flows to spill into bypasses, away from towns and structures. The SRFCP, in conjunction with major headwater dams constructed in the mid-twentieth century, is still relied on for flood protection in Sacramento today. At the same time, major storms such as those in 1986 and 1997 have exposed weaknesses in the system. A better understanding of regional hydrology and geotechnical engineering has led to a downgrading of the estimates of risk reduction offered by the dams and levees. Managing the Sacramento area s flood risk means protecting the population and substantial investment that have grown over time in the region. The City of Sacramento is the sixth-largest city in California and has a population exceeding 485,000 in a 100-square-mile area (DOF, 2016; City of Sacramento, 2014). The American River Common Features General Reevaluation Report (ARCF GRR) estimated that in the 200-year floodplains for Natomas and the American River, which extend beyond the city limits, the population at risk is 501,000 during the day and 580,000 at night (USACE, 2016). Within the 500-year floodplain, the GRR showed $64.4 billion in damageable property. A 2007 Independent Review Panel recommended that communities be protected against the Standard Project Flood (SPF), the flood resulting from the most severe combination of meteorologic and hydrologic conditions reasonably characteristic of a region (Independent Review Panel, 2007). In the Central Valley this was considered to fall between the 200- and 500- year return periods. Panel member Dr. Gerald Galloway had previously recommended the use of the SPF while serving as a Brigadier General in the US Army chairing a committee reviewing 1993 flooding in the Midwest. The SPF standard is consistent with the 2015 Executive Order 13690, which establishes a 500-year flood as the protection standard unless a specified alternative calculation is used. Sacramento s Comprehensive Flood Risk Reduction Program 2

4 The Sacramento Area Flood Control Agency (SAFCA) was formed to address the Sacramento area s flood vulnerabilities demonstrated in the severe flows of SAFCA s Joint Exercise of Powers Agreement established its goal of achieving an interim of 100-year protection leading to at least 200-year protection for the region. SAFCA s structural program can be divided into three overlapping phases, each of which builds upon previous and ongoing flood management efforts. In its first phase, now completed, SAFCA worked with partners to raise and strengthen levees and reoperate Folsom Dam to resolve deficiencies revealed in the floods of These deficiencies included through-levee seepage and levee height. In its second phase, now well underway, SAFCA has worked toward 200-year protection for the region by continuing to bolster levees and address underseepage and other hazards brought into the spotlight by 1997 flooding, as well as to improve Folsom Dam and adjust its operations. SAFCA is now just starting its third phase in order to provide 500-year protection, which includes increasing conveyance downstream of Folsom Dam, investigating additional flood storage in reservoirs above Folsom, and implementing comprehensive system wide levee operations, maintenance, repair, replacement, and rehabilitation (OMRR&R) measures. These structural measures are the backbone of a comprehensive flood risk management program for this floodplain-occupying city that also includes a complementary suite of non-structural measures focusing on land use planning, emergency management, risk communication, and insurance. The most important document for the non-structural measures is the Comprehensive Flood Management Plan (CFMP) (City of Sacramento, 2016), which builds upon floodplain conservation and land use measures included in the City s general plan and floodplain management ordinance, as well as other emergency planning documents prepared by the land use agencies. Based on SAFCA s analysis to date, the structural actions being implemented and planned by SAFCA and its partners would meet the 500-year federal flood risk management standard for flooding from the American and Sacramento rivers. The implementation of the CFMP will help manage residual risks and will address tributary flooding and internal drainage not otherwise addressed by SAFCA s structural actions. Sacramento s Comprehensive Flood Risk Reduction Program 3

5 Figure 1: Regional Location Sacramento s Comprehensive Flood Risk Reduction Program 4

6 Figure 2: Sacramento Area - Elements of Flood and Residual Risk Management Sacramento s Comprehensive Flood Risk Reduction Program 5

7 2. FLOOD SYSTEM MANAGEMENT SAFCA is the local partner implementing a variety of flood system management projects consistent with the following three goals called out in the Engineer s Report for SAFCA s Consolidated Capital Assessment District No. 2 (WSP Parsons Brinckerhoff, 2016): (1) Complete the projects necessary to provide 100-year flood protection for developed areas in Sacramento s major floodplains as quickly as possible; (2) Achieve the State of California s 200- year flood protection standard for these areas within the timeframe allowed by the Legislature; and (3) Improve the resiliency, robustness and structural integrity of the flood control system over time so that the system can safely contain flood events larger than a 200-year flood. American and Sacramento Rivers and Tributaries Table 1 shows SAFCA s flood risk management approach in three overlapping phases of structural projects, with successive efforts building on previously-completed work. Federal project authorizations are listed in Appendix A. SAFCA s first steps in its initial decade led to the raising and strengthening of area levees to address levee through seepage along the Sacramento River, erosion along the American River, and levee system (height and extent) deficiencies in the Natomas basin and the northern part of the region. SAFCA also entered an agreement with the U.S. Bureau of Reclamation to reserve more flood space in Folsom Reservoir when upstream reservoirs are full (variable storage). These successes almost certainly avoided a flood catastrophe when major storms hit again in SAFCA embarked on its current core 200-year program (Figure 3) in The core program includes continued raising and strengthening of area levees and is designed to protect against underseepage with cutoff walls, berms, and relief wells along the American and Sacramento rivers and portions of their tributaries. In addition, the program incorporates the Folsom Dam Modifications project, which has led to the construction of an auxiliary spillway to allow earlier discharge of high volume flows from the dam, optimizing use of the storage capacity to lower peak discharges at the critical part of the flood hydrograph. The project will also implement a new water control manual to use weather forecasts to guide the use of variable flood control space. Also incorporated is the Folsom Dam Sacramento s Comprehensive Flood Risk Reduction Program 6

8 Raise project, which will add an additional increment of storage capacity. SAFCA is now planning for 500-year protection even as it completes its 200-year protection projects (Figure 4). This additional protection will be achieved in large part by increasing the capacity of the flood control system downstream of Folsom Dam. Along the Lower American and Sacramento Rivers, the Water Infrastructure Investment for the Nation Act of 2016 includes an authorization that can accommodate emergency releases of up to 160,000 cubic feet per second (cfs) from Folsom Dam by increasing the erosion resistance of the leveed portion of the American River channel and by widening Sacramento Weir and Bypass to take pressure off the levee system along the Sacramento River downstream of I Street. Flows in the Sacramento River upstream of I Street to the mouth of the Natomas Cross Canal could be lowered by widening the Fremont Weir and upper end of the Yolo Bypass pending the adoption of a project. Planning efforts are looking at ways that these improvements to the levee system downstream of Folsom Dam could be augmented by increasing the reservoir storage space available for flood control in the three largest non-federal dams upstream of Folsom Union Valley Dam owned by the Sacramento Municipal Utility District (SMUD), and French Meadows Dam and Hell Hole Dam, both of which are owned by the Placer County Water Agency (PCWA). These dams are currently operated for hydropower and water supply purposes and only incidentally provide flood control benefits depending on antecedent rainfall conditions. The concept of adding flood control as a purpose was analyzed in the 1996 Supplemental Information Report on the American River Watershed by USACE (USACE et al., 1996). The analysis concluded that an additional 300,000 acre-feet of seasonal flood storage space could be created by modifying the outlet works of each of the facilities. However, the analysis assumed that this space would have to be created each year and the resulting loss of hydropower and water supply benefits made it infeasible to do this. SAFCA believes that advances in hydrologic forecasting capabilities in the region could overcome this problem. The outlet modifications analyzed by USACE would allow evacuation of the requisite reservoir storage space over a three to four day period. Assuming this space is needed only in the most extreme flood events (greater than 200-year), the evacuation could be tied to a 5-day or 7-day forecast of such an event and the annual losses of hydropower and water supply benefits that defeated this alternative in the USACE analysis could be avoided. SAFCA s flood routings indicate that this sort of forecast informed operation could be incorporated into the inflow forecasts that will drive the new Folsom Dam water control manual without requiring any major adjustment in the manual. Accordingly, if funding for the necessary outlet work modifications can be secured, operation plans for the three upstream dams could be negotiated through agreements between SAFCA and SMUD and PCWA. Under these agreements the operators would make the specified reservoir storage space available under the specified extreme circumstances and SAFCA would provide annual compensation to these entities to cover their increased operation and maintenance costs and offset whatever risk of loss they might incur. Operations and Maintenance System wide levee OMRR&R measures are not uniformly quantifiable in terms of their effect on floodway capacity or levee reliability. However, they will help maintain the desired level of protection over time and provide resiliency for the system. Operation and maintenance of the Sacramento s Comprehensive Flood Risk Reduction Program 7

9 Table 1: Structural Flood Management Projects See Appendix A for Authorizations Phase Approach Description of Project Elements First Steps ( ) 200-Year Flood Protection ( ) 500-Year Flood Protection ( ) Raise and strengthen area levees to address post-1986 flood deficiencies Reoperate Folsom Dam Raise and strengthen area levees to address underseepage and other post-1997 flood deficiencies Modify Folsom Dam and implement forecast informed operations Increase the conveyance capacity of the flood control system downstream of Folsom Dam Secure additional reservoir storage space for flood control upstream of Folsom Dam Implement System Wide Levee OMRR&R Measures Install cutoff walls and landside drainage berms along 33 miles of the east levee of the Sacramento River between Verona and Freeport to control levee through seepage Raise portions of the levee system along the Natomas East Main Drainage Canal (NEMDC), Arcade Creek, and Dry/Robla Creek in Natomas and North Sacramento to control high flows in the American River and these north area tributaries Construct a new levee along the north side of Dry Creek and a new pumping facility in the NEMDC at Dry Creek to prevent overflows into the Natomas Basin and rural areas north of Dry Creek Construct environmentally acceptable bank protection projects to control erosion at 5 sites along the Lower American River Until such time as a comprehensive flood control plan for the American River is implemented, enter into an agreement with the U. S. Bureau of Reclamation to increase the storage space for flood control in Folsom Reservoir when such storage space is unavailable in the largest non-federal reservoirs in the watershed Install underseepage cut-off walls along 20 miles of the levees of the American River, raise a portion of the north levee and construct a new levee and closure structure along the south side of the river at the Mayhew Drain Raise portions of the 42-mile perimeter levee system around the Natomas Basin, construct a new adjacent levee along the Sacramento River reach of the system, install underseepage cutoff walls and underseepage control berms in all reaches, and reconstruct all drainage and irrigation pumping facilities serving the Basin Install underseepage cutoff walls and relief wells along a 6-mile segment of the Sacramento River east levee in the Pocket area and construct bank protection as needed to resist boat wake and flow generated erosion in this reach Install underseepage cutoff walls along 4 miles of the NEMDC and Arcade Creek levees in North Sacramento Raise and strengthen the 4 miles of the Beach Lake levee and construct 10 miles of raised floodwalls along Morrison Creek and its tributaries in South Sacramento Construct a new approach channel, auxiliary dam, spillway, and stilling basin to increase Folsom Dam s low level outlet capacity Raise the height of Folsom Dam by 3.5 feet to create more reservoir storage space for flood control Implement a new water control manual allowing Folsom Dam operators to release water through the new auxiliary spillway and increase the reservoir space available for flood control based on forecasted inflows to Folsom Reservoir Protect the leveed portion of the American River channel from erosion as necessary to allow the channel to safely convey sustained flows of 160,000 cfs during the most extreme flood events in the watershed Widen the Sacramento Weir and Bypass to accommodate the increased conveyance capacity of the American River channel and lower flows in the Sacramento River channel downstream of the I Street Bridge Widen the Fremont Weir and portions of the Yolo Bypass to increase the conveyance capacity of the bypass and lower flows in the Sacramento River channel upstream of the I Street Bridge Negotiate agreements with the owners of the three largest non-federal reservoirs in the American River watershed French Meadows, Hell Hole and Union Valley to modify the outlet works of these facilities so as to allow the operators to release stored water as necessary to secure 200,000 to 300,000 acre feet of storage space in these reservoirs when forecasted inflows indicate the probability of a flood exceeding the magnitude of a 200-year event Remove hazardous vegetation and encroachments from area levees Acquire rights to establish continuous access to the landside toe of all state-federal project levees in the area Create sufficient reserve funding to ensure long term operation, maintenance, repair and rehabilitation of all state-federal project levees in the area Sacramento s Comprehensive Flood Risk Reduction Program 8

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11 Figure 3: SAFCA 200-year Flood Management Projects Sacramento s Comprehensive Flood Risk Reduction Program 10

12 Figure 4: SAFCA 500-year Flood Management Projects Sacramento s Comprehensive Flood Risk Reduction Program 11

13 facilities protecting the region has been conducted by the appropriate entities, including the US Bureau of Reclamation (USBR) and DWR for the headwaters dams, DWR and CVFPB for bypasses and for levees within designated State Maintenance Areas, and the City of Sacramento and local Reclamation Districts for other levees and facilities. Reclamation District 1000 (RD1000) maintains Natomas Basin levees and the American River Flood Control District (ARFCD) maintains the remaining levees on the American River. SAFCA s recently established assessment district will fund a broad range of flood control system operation and maintenance activities and repair and rehabilitation measures. These include actions by SAFCA and local maintaining agencies such as routine levee maintenance, bank protection, system access, levee monitoring, flood fighting, repair or rehabilitation of damaged infrastructure, and encroachment and vegetation management. The assessment district also will fund operation and maintenance of the Folsom Dam Modifications Project and the Folsom Dam Raise Project which will be performed by USBR. Levee Security California s Urban Levee Design Criteria (DWR, 2012) require local maintaining agencies (LMAs) to provide security plans for urban areas to protect against terrorism and other malicious acts. The CFMP meets the ULDC requirements by describing the City s measures for networked detection, deterrence, physical security, and intrusion detection of City features. Similar actions are being undertaken by the other LMAs in the region. 3. LAND USE SAFCA preserves open space in conjunction with levee improvements and reduces flood probability in step with new development. The City and County, as well as Sutter County, have land use approval authority. Growth Management SAFCA s flood system management incorporates substantial open space and habitat preservation, particularly in the agricultural areas of the Natomas Basin. This serves multiple purposes, including mitigating the habitat impacts of the project, providing space for levee maintenance and future upgrades, and reducing the footprint for urban development within the basin. Habitat Conservation Plans (HCPs) require that land use agencies (the City and Sacramento and Sutter counties) pay for the preservation of at least half an acre of open space in the basin for each acre that is developed. The Natomas Basin HCP was itself a mitigation for the USACE-issued Clean Water Act Section 404 permit for SAFCA s North Area Local Project (City of Sacramento et al., 2003). Between the HCPs, SAFCA s open space, and the Sacramento International Airport bufferlands, development is restricted to only about 60% of the basin. Sacramento s Comprehensive Flood Risk Reduction Program 12

14 The Sacramento 2035 General Plan (City of Sacramento, 2016), based on previously adopted smart growth principles, favors developing inward over expanding outward into greenfields on the edge of the city. The city s growth pattern will be more compact [and will] include the infill and reuse of underutilized properties. To manage flood risks in conjunction with this intensification of use, SAFCA has created a Development Impact Fee (DIF). The DIF applies to new development within the levee-protected areas in the city and county, as well as Sutter County, and funds flood risk reduction projects. The DIF-funded projects are intended to keep flood risk (risk is the product of the probability of flooding and its consequences) from increasing even as more investment is made in damageable property in the region. As a result, the level of flood protection will rise (the probability of flooding will drop) to keep pace with new development (increasing consequences). Urban Levee Zoning California s Urban Levee Design Criteria are intended to guide land use agencies and LMAs to obtain or preserve adequate room at the landside toe of a levee for maintenance, inspection, patrolling, and flood fighting. The criteria also encourage protecting additional right-of-way width for future expansion and to control activities that could endanger the integrity of a levee or floodwall. SAFCA has met these objectives while upgrading levees in the undeveloped areas of the Natomas Basin. This basin contains the northern part of Sacramento. In addition, the Levee Modernization program described in SAFCA s Urban Level of Flood Protection Plan (SAFCA, 2016) identifies how landside toe access and visibility will be expanded over time. To restrict new development from encroaching on levees, the City of Sacramento Zoning Code establishes a 20-foot building setback from the landside toe of a levee for new development less than five acres in size and a 50-foot setback for developments over five acres. Refuge Areas The City s CFMP calls for new development to include refuge areas within flood rescue and evacuation areas. The City s building code (City of Sacramento, 2016a), requires compliance with the CFMP and states that new public facilities and commercial buildings greater than 40,000 square feet shall have an accessible roof or floor level at least one foot above the rescue flood elevation. A rescue area is an area where the flood can reach a foot or more in depth within two hours of a levee failure. New subdivisions larger than two acres in rescue areas must identify refuges within a mile of all residences, have floor levels at least one foot above the rescue flood elevation, or have half of the residential roofs pitched no steeper than 4 of rise for each horizontal foot. The City is in the process of updating its Floodplain Management Ordinance to further address development and access in rescue and evacuation areas (City of Sacramento, 2016). Sacramento s Comprehensive Flood Risk Reduction Program 13

15 Hazard Mitigation For areas within the 100-year floodplain, the CFMP requires mitigating flood risk through elevation, structure relocation, or floodproofing. These requirements are codified in the floodplain management ordinance, which is intended to comply with federal floodplain management criteria prescribed in Part 60 of Subchapter B of Title 44 of the Code of Federal Regulations. The floodplain management ordinance does not allow new development to increase flood levels for the base flood. It also specifies that the lowest floor of new construction should be one foot above the 100-year flood elevation. Alternatively, nonresidential construction may be dry or wet floodproofed and designed to withstand the loads and buoyancy effects of the surrounding water. Hazardous materials facilities in the City have been inventoried in the Sacramento County Local Hazard Mitigation Plan (LHMP) (Sacramento County, 2016). The City general plan requires that new proposals for hazardous materials facilities be reviewed for and mitigate significant risks (City of Sacramento, 2015). The City s Emergency Operations Plan (EOP) describes the Urban Search and Rescue California Task Force 7, a FEMA task force that is equipped for both swift water rescue and hazardous materials incidents. In addition, the City hosts two Type 1 Hazmat Teams (the highest level of training and equipment) and has a mutual aid agreement with Metro Fire which has an additional team. The EOP also outlines a debris management function that will identify hazardous materials and ensure proper disposal and worker/responder safety. 4. EMERGENCY MANAGEMENT The City of Sacramento has prepared or collaborated in the preparation of a variety of emergency and flood management plans to help prepare for, respond to, and recover from disasters. The most germane to flooding is the CFMP (City of Sacramento, 2016), which guides flood risk reduction efforts through Other important references are the County Local Hazard Mitigation Plan (County of Sacramento, 2016), which identifies the hazards the county and its cities face; the County and City Emergency Operations Plans, which follow California Emergency Management Agency (Cal EMA) and Federal Emergency Management Agency (FEMA) guidelines on how to respond to an emergency from onset through recovery; and the regional and City Flood Emergency Action Plans, which describe how the agencies will respond to flood emergencies, including preparedness, patrol, flood fight, evacuation, and floodwater removal. Flood Preparedness Flood preparedness begins with flood hazard mapping. The City s CFMP describes and provides links for available flood maps, including those for FEMA floodplains, State 200-year floodplains, and levee break scenarios (City of Sacramento, 2016). The levee break scenarios include maps of evacuation routes and time estimates for flooding of affected areas. The February 2017 evacuation of areas below Oroville Dam has illustrated how challenging a mass evacuation can be. The City has anticipated this and has also taken advantage of geographic assets like its many state, federal, and interstate highways, as well as natural high ground east of Sacramento s Comprehensive Flood Risk Reduction Program 14

16 the City, to plan for rapid evacuation of greater, more densely situated populations. More detailed maps the City has made available on the internet also include the location of critical facilities and vulnerable populations, including schools, hospitals, fire stations, and law enforcement offices (City of Sacramento, 2017). Additional vulnerable populations as well as hazardous materials facilities have been inventoried in the LHMP (Sacramento County, 2016). The City s CFMP details emergency management action items. These include preparedness activities such as continuing National Incident Management System (NIMS) and Standardized Emergency Management System (SEMS) exercise and training as well as other exercises, emergency and recovery planning, and expanding the EOP to address mass care, emergency assistance, housing, and human services. The CFMP also describes internal storm drainage systems the City relies on to get surface runoff to points at which it can be pumped over levees into the major rivers. As the CFMP notes, the flooding these systems protect against has less potential for catastrophic damage than the major rivers have, but property damage can result from failures of internal drainage systems. The CFMP identifies proposed internal drainage projects on the City s Capital Improvement Project (CIP) backlog list and establishes action items to develop funding for these projects and update master plans. Flood Warning The CFMP describes the City s flood warning system. The City uses the California Data Exchange Center (CDEC), which operates an extensive hydrologic data collection network, for flood forecasting information. The City uses the Automated Local Evaluation in Real Time (ALERT) system created and maintained by the City and County of Sacramento to monitor local Sacramento s Comprehensive Flood Risk Reduction Program 15

17 creeks and rainfall for flooding conditions. As described in the CFMP, the City s floodplain management ordinance requires approval of a flood warning and response plan for special needs facilities prior to occupancy in the City s Rescue and Evacuation Areas. The CFMP establishes a long-term goal of enhancing public alert and notification of emergencies. Emergency Response The CFMP describes emergency response functions, including activation of the Emergency Operations Center (EOC). Emergency response is described in greater detail in the EOP, which has established the key functions during an emergency and assigned responsibility to the appropriate departments. The City s response is organized under the guidelines of NIMS, SEMS, and the Incident Command System (ICS), and is coordinated with the County and with the State Office of Emergency Services pursuant to NIMS. In a flood emergency, the City Manager and Emergency Services Department have primary responsibility for incident direction and control. The City Department of Utilities (DOU) is responsible for monitoring City levees and drainage facilities and responding to utility failures. DOU findings are reported to the City Police and Fire departments, which are responsible for communications, public safety, and managing evacuation efforts as required. The CFMP lists development of intergovernmental flood management and control as an action item. Within the City limits, different levee reaches are managed by the City, the American River Flood Control District, Reclamation District 1000, and State Maintenance Area 9. Each of these agencies maintains its own flood fight and response capability, including the ability to call in outside contractors as needed during an event. Outside the City limits, the City is dependent on County, State, and federal facilities, including those managed or operated by the US Army Corps of Engineers and US Bureau of Reclamation. Recovery from a flood event will include hazard mitigation, as outlined in both the LHMP and the CFMP. Impacted areas will be identified, and safety assessments will be prepared for impacted structures using the Applied Technology Council (ATC) ATC-45 Field Manual. City and other public utilities and facilities will be assessed and repaired or returned to operation as needed. Debris will be removed from transportation routes, storm drains, and other water conveyances. Hazard mitigation will involve the City Code Compliance Division staff to issue permits for home repair and reconstruction pursuant to the terms of the Floodplain Management Ordinance and the National Flood Insurance Program. Hazard mitigation assistance will be sought through FEMA, the California Office of Emergency Assistance, and other sources as applicable. Sacramento s Comprehensive Flood Risk Reduction Program 16

18 5. RISK COMMUNICATION The CFMP describes the Program for Public Information (PPI) developed as part of the City s participation in the Community Rating System (CRS) of the National Flood Insurance Program (NFIP). The PPI is designed to convey information about the flood hazards Sacramento faces, flood preparation, available insurance, flood protection methods, evacuation areas, floodwater contamination issues, and reconstruction requirements. The PPI is targeted towards various audiences encompassing the entire City. Businesses, homeowners, and renters are primary targets. Additional communications are targeted at school children. Real estate agents, lenders, and insurance agents were part of the PPI Committee and are also targeted audiences. Vulnerable populations who may have difficulty evacuating have been identified for outreach. Political leaders are targets for information that can inform flood policy and funding. The CFMP identifies 28 projects for flood awareness and readiness. These projects range widely, from outdoor signage like high water mark signage and signboards on buses, to mailers and newsletters. More interactive messaging is delivered via community events and websites. Once flooding is imminent, the City implements several identified flood response information projects. The Sacramento Alert program notifies residents by phone, , and text message during and after a flood. Press releases are developed for television, radio, newspapers, and social media. Handouts are distributed in the field. Signage is posted after flooding of the combined sewer system to deter people from entering contaminated water. A drinking water quality incident response plan is also implemented to educate residents of affected areas to avoid consuming contaminated water after a flood. 6. NATIONAL FLOOD INSURANCE PROGRAM The NFIP is a program that local communities (cities and counties) can join so that their citizens can benefit from flood mapping (the Flood Insurance Rate Maps) and federal flood insurance. The City of Sacramento joined the NFIP in It also participates in the CRS, which offers communities lower flood insurance premiums if they implement measures to lower flood risk beyond the basic NFIP requirements. There are 10 CRS classes for participating communities. Class 10 is for communities that have no or few optional programs and therefore do not receive NFIP insurance reductions. Class 1 communities, by contrast, participate in many activities to reduce flood risk and enjoy a 45% Sacramento s Comprehensive Flood Risk Reduction Program 17

19 reduction in insurance premiums for structures in Special Flood Hazard Areas (SFHAs). The City of Sacramento is currently rated at CRS Class 5, corresponding to a flood insurance premium reduction of up to 25%, and the CFMP includes an action item to move towards a level 3 or 4 designation, along with eleven other action items supporting the NFIP and CRS programs. The County of Sacramento is rated at class 3, with a 35% flood insurance premium reduction, one of the highest nationwide. Both communities are actively working to further improve these already noteworthy ratings. 7. PLANNED OUTCOMES Flood risks in the Sacramento area originate primarily from the two major rivers, the Sacramento River and the American River. For over a century, the first line of defense against flooding on these systems has been the SRFCP, now operating in conjunction with major state and federal dams on the mainstem rivers, including Folsom Dam on the American River just above the city. SAFCA has studied the combined ability of these systems to manage floods in the Sacramento region. On the Sacramento River, SAFCA has contracted David Ford Consulting Engineers to analyze 500-year flood flows in the channel. The water surface elevation results, shown in Figure 5 along with the left bank (east levee) top-of-levee and channel invert profiles, demonstrate that with the implementation of SAFCA s identified projects, future flows can generally be kept within the levees along the Sacramento River during the 500-year event (David Ford Consulting Engineers, 2017). This analysis factors in a climate change scenario and assumes that upstream levees do not breach and thus relieve pressure on the river reach in the Sacramento area. Figure 5 shows that the majority of the Sacramento River frontage has at least three feet of freeboard, with a low spot just above the Freeport Bridge, and some low spots upstream and downstream of the Capitol Mall Bridge in the vicinity of Old Sacramento. The low spots in most cases still provide at least two feet of freeboard. Because of the minor nature of these low spots, SAFCA expects to be able to correct these over time with a combination of levee armoring to provide resilience against minor overtopping and minor levee or floodwall raising. This could be accomplished as part of the OMRR&R planned to provide 500-year protection. The 500-year flows on the American River of the most concern are the peak 3-day flows. SAFCA has retained MBK Engineers (MBK, 2017) to analyze the effectiveness of the proposed structural flood management projects on the American River. MBK first analyzed the Folsom Dam Modifications and the Folsom Dam Raise Projects and the armoring of the Lower American River as described in the American River Common Features General Reevaluation Report. MBK s analysis concluded that under current hydrology these improvements would adequately contain 500-year flood flows within the channel with a 160,000 cfs release from Folsom. However, climate change is projected to increase peak 500-year flows by about 14 percent, potentially causing the 160,000 cfs flow threshold in the Lower American River to be exceeded without further improvements. MBK separately analyzed the benefits of managing Sacramento s Comprehensive Flood Risk Reduction Program 18

20 upstream reservoir storage to augment flood storage in the watershed and moderate peak flows out of Folsom. Based on this separate analysis, outlet modifications and forecast-informed reoperation of the Union Valley, Hell Hole, and French Meadows reservoirs could help manage peak inflows to Folsom. Although the combined analysis of the suite of measures (Folsom Dam Modifications, ARCF GRR, and upstream reservoir management) is not yet complete for a future climate change scenario, the two separate analyses suggest that the combined measures could advance the flood protection provided by Folsom Dam to near the level at which releases could be held at or below 160,000 cfs in the 500-year event with climate change. Lesser, localized risk is presented to Sacramento by the smaller tributaries to the major rivers and by internal drainage within the levee-protected areas. The City of Sacramento has the primary responsibility for protecting its citizens from these risks and is doing so as described in the CFMP. Sacramento s Comprehensive Flood Risk Reduction Program 19

21 Figure 5: Sacramento River 500-year Flood Profile Sacramento s Comprehensive Flood Risk Reduction Program 20

22 8. REFERENCES City of Sacramento, et al. (City of Sacramento, Sutter County, and Natomas Basin Conservancy) Final Natomas Basin Habitat Conservation Plan. Prepared in association with Reclamation District No and Natomas Central Mutual Water Company. Prepared for United States Fish and Wildlife Service and California Department of Fish and Game. April. Accessed 2/26/2017 at City of Sacramento Sacramento 2035 General Plan Background Report. Public Review Draft. August. City of Sacramento Sacramento 2035 General Plan. Adopted March 3. Accessed 2/17/2017 at Library/General-Plan. City of Sacramento Sacramento City Code Title 15 Buildings and Construction Chapter Accessed 2/16/2017 at City of Sacramento Comprehensive Flood Management Plan. Department of Utilities. February. Accessed 2/13/2017 at /media/corporate/files/dou/flood-ready/2016-cfmp.pdf?la=en. City of Sacramento Sacramento City Code Title 17 Planning and Development Code Division II Zoning Districts and Land Use Regulations. Accessed 2/16/2017 at City of Sacramento Flood Depth and Evacuation Maps. Online resource accessed 2/17/2017 at County of Sacramento Sacramento County Local Hazard Mitigation Plan Update. December. Accessed on 2/16/2017 at Committee-2016-Plan-Update.aspx. David Ford Consulting Engineers [River stage modeling of the Sacramento River]. Unpublished raw data. February. DOF (California Department of Finance) Tables of January 2016 City Population Ranked by Size, Numeric and Percent Change. Demographic Research Unit. May 1. Accessed 1/26/2017 at DWR (California Natural Resources Agency Department of Water Resources) Urban Levee Design Criteria. May. Sacramento s Comprehensive Flood Risk Reduction Program 21

23 Independent Review Panel A California Challenge Flooding in the Central Valley. A Report to the Department of Water Resources, State of California. Dr. Gerald E. Galloway, Jr., P.E., Chair. October 15. Interagency Floodplain Management Review Committee Sharing the Challenge: Floodplain Management into the 21 st Century. Report of the Interagency Floodplain Management Review Committee to the Interagency Floodplain Management Task Force. June. LWA (Larsen Wurzel & Associates, Inc.) Sacramento Area Flood Control Agency American River Basin Plan Levee Accreditation Project Urban Risk Reduction Program Concept Proposal. Prepared for The Sacramento Area Flood Control Agency. March 9. MBK (MBK Engineers) [Routing analysis of flood flows in the American River]. Unpublished draft memo. February. SAFCA (Sacramento Area Flood Control Agency) Sacramento Area Flood Control Agency Final Urban Level of Flood Protection Plan and Adequate Progress Baseline Report. June 10. USACE (United States Army Corps of Engineers) and David Ford Consulting Engineers Central Valley Hydrology Study. Prepared for California Department of Water Resources Letter of agreement # November 29. USACE, California Reclamation Board, and SAFCA Supplemental Information Report American River Watershed Project, California. March. USACE American River Watershed Common Features General Reevaluation Report. Final Report. Sacramento District. December. Accessed 3/17/2017 at F_GRR_Jan2016.pdf USACE Sacramento General Reevaluation Report. Webpage. Accessed 2/20/2017 at WSP Parsons Brinckerhoff Engineer s Report Sacramento Area Flood Control Agency Consolidated Capital Assessment District No. 2. Prepared for Sacramento Area Flood Control Agency. June 13. Sacramento s Comprehensive Flood Risk Reduction Program 22

24 APPENDIX A: TABLE OF AUTHORIZATIONS Phase Approach Authority First Steps ( ) Raise and strengthen area levees to address post-1986 flood deficiencies Repairs against through seepage were determined to be design deficiencies that could be repaired under the original SRFPC project authorization. North area levee raises, a new levee on the north side of Dry Creek, and the NEMDC pumping facility were authorized by Section 9159 of the Department of Defense Appropriations Act of 1993 (Public Law ) 200-Year Flood Protection ( ) Reoperate Folsom Dam Raise and strengthen area levees to address underseepage and other post-1997 flood deficiencies Bank protection is authorized by the Flood Control Act of 1917, Pub. L , 2, 39 Stat. 948, 949, as modified by the Water Resources Development Act, Pub. L , 3031, 121 Stat (2007) Water Resources Development Act of 1996, PL Oct. 12, 1996, 110 STAT Underseepage repairs were authorized by section 101(a)(1) of the Water Resources Development Act of 1996 (Public Law ) and Water Resources Development Act of 1999, PL AUG.17, 1999, 113 STAT Natomas levee improvements were authorized in Section 7002 of the Water Resources Reform and Development Act of 2014 (Public Law ) Underseepage improvements on the Sacramento River east levee and NEMDC and Arcade Creek levees were authorized in the Water Infrastructure Improvements for the Nation Act of 2016, (Public Law Dec 16, 2016). Improvements on the South Sacramento Streams Group were authorized by Water Resources Development Act of 1999, PL AUG.17, 1999, 113 STAT Sacramento s Comprehensive Flood Risk Reduction Program 23

25 Phase Approach Authority Modify Folsom Dam and implement forecast informed operations Water Resources Development Act of 1999, PL AUG.17, 1999, 113 STAT The raise was authorized in the Energy and Water Development Act of 2004, PL Dec 13, 2003, 177 STAT Year Flood Protection ( ) Increase the conveyance capacity of the flood control system downstream of Folsom Dam Secure additional reservoir storage space for flood control upstream of Folsom Dam Implement System Wide Levee OMRR&R Measures Section 3029 of the Water Resources Development Act of 2007 (Public Law ) Erosion protection and widening the Sacramento Weir and Bypass were authorized in Section 1401 of the Water Infrastructure Investment for the Nation Act of 2016 (Public Law Dec 16, 2016). The Fremont Weir and Yolo Bypass widening are not yet authorized. Not yet authorized. OMRR&R measures are authorized by the original project authorizations. Sacramento s Comprehensive Flood Risk Reduction Program 24