EXECUTIVE SUMMARY ES.1 INTRODUCTION

Transcription

1 ES.1 INTRODUCTION The purpose of this Wastewater Collection System Master Plan (Master Plan) is to provide the City of Lake Oswego (City) a plan for management and operation of their wastewater collection system for the future. The City has spent several years planning for and constructing the rehabilitated Lake Oswego Interceptor Sewer (LOIS). As construction of the LOIS comes to a close, the City needs a plan for the remainder of its aging wastewater infrastructure. This Master Plan evaluated the condition and capacity of the wastewater collection system and developed feasible alternatives to mitigate the identified system deficiencies while planning for the necessary future expansion of the system. The Master Plan was initiated in 2010 and developed during 2011 for final approval in The selected planning period begins in 2010, the year the planning started, and evaluates short-term improvement needs (Year 2020), long-term improvement needs (Year 2045), and build-out conditions. The scope of this Master Plan update included the following main tasks: Policy & Criteria Review; Flow Projections; Model Development; Condition Assessment; Capacity Evaluation; Capital Project Development. The City is located along the west bank of the Willamette River, just south of the City of Portland. The City owns, maintains, and operates gravity wastewater pipelines, pump stations, and septic tank effluent pumps (STEPs). The City collects wastewater from residential, commercial, institutional, and industrial customers within the service area. For purposes of evaluation and planning, the City s wastewater collection system has been subdivided into 22 wastewater collection basins. The City does not own a wastewater treatment plant. The majority of the City s wastewater flow is conveyed to the City of Portland s Tryon Creek Wastewater Treatment Plant (WWTP), located in Lake Oswego, where the City s flow is measured and treated. The remainder of the City s flow (approximately 12 percent) is conveyed to Clean Water Services (CWS) Durham Advanced Wastewater Treatment Facility in the City of Tigard. Figure ES.1 illustrates the City s current Wastewater Service Area and wastewater treatment service providers. The City of Portland s Bureau of Environmental Services (BES) provides service to the north of the City, while CWS provides service to areas to the west of the City. Clackamas County District No.1 provides service to areas southeast of the City. Additionally, the Dunthorpe-Riverdale Service District (operated by BES) provides service to the northeast. CAROLLO ENGINEERS ES-1 DRAFT - October 18, 2012

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3 ES.2 POLICIES & CRITERIA The City is responsible for managing and operating its wastewater system in accordance with all known local, state, and federal regulations. To best manage the wastewater system and meet the regulations, the City has adopted wastewater system policies and criteria. These policies and criteria guide the development and financing of the infrastructure required to provide wastewater service. The policies also guide the City s commitments to current wastewater system customers, as well as those considering service from the City. Criteria are established to provide a consistent approach to evaluating the wastewater system. Chapter 2 of the Master Plan summarizes the City s existing policies and criteria. The existing and recommended policies include maintaining several programs that help in the management of the wastewater system. These include the Emergency Response Plan, Vulnerability Assessment and Hazard Mitigation Plan; Fats, Oils, and Grease (FOG) Program; and Infiltration and Inflow (I/I) Reduction Program. Recommendations for creating and/or updating these programs are included in Chapter 8 Capital Improvements Plan of the Master Plan. Several wastewater system policies and criteria are recommended to supplement existing policies; these include modifications to the policies pertaining to septic tank effluent pump (STEP) systems and services, and developing wastewater system design standards. Additionally, new policies are recommended for implementation, such as improving system reliability, environmental stewardship, and coordination with other agencies. Adopting these policies will take City staff time and effort, and will incorporate public review. The Master Plan establishes specific criteria for evaluating the capacity of the wastewater collection system. These criteria were established working with City staff. The following three criteria are the most critical for the capacity evaluation, which is the basis for identifying necessary improvement projects: The wastewater system facilities will be designed to adequately and reliably convey peak hour flows associated with a 25-year, 24-hour recurrence frequency storm event without overflowing or discharging to any water bodies. The City Engineer may permit using a smaller 5-year, 24-hour or 10-year, 24-hour recurrence frequency storm event for some facilities on a case-by-case basis. The Oregon State Department of Environmental Quality (DEQ) currently requires elimination of sewer overflows but does not currently issue fines if the wastewater collection system is designed to convey the peak flow resulting from a 5-year, 24-hour winter storm event. However, in an effort to reduce or eliminate surcharging and sewer overflows, the City has established that the Master Plan should evaluate the capacity of the system using a larger 25-year, 24-hour storm event. All pump stations, except for private stations for a single-family home, shall have a minimum of two pump units, each with the capacity to handle the expected maximum flow. CAROLLO ENGINEERS ES-3 DRAFT - October 18, 2012

4 The capacity of existing pipes in the collection system shall be defined for two conditions, as follows: At Peak Dry Weather Flow (PDWF), pipes can flow full with a depth to full depth (d/d) ratio of 0.92, At Peak Wet Weather Flow (PWWF), the Hydraulic Grade Line (HGL) may not rise above three feet below any manhole rim. ES.3 EXISTING SYSTEM AND CONDITION ASSESSMENT The City operates and maintains approximately one million feet of wastewater pipes, 12 pump stations, and 21 septic tank effluent pumps, as shown in Figure ES.2. These include the improvements associated with the LOIS project, which were completed during preparation of this Master Plan. A preliminary condition assessment was performed for the City s existing major collectors, pump stations, and STEPs. The condition assessment reviewed the age, estimated remaining useful life, and recent maintenance records of the City s major collection system infrastructure. The assessment is useful for identifying improvement projects to extend the useful life of City infrastructure, and prevent failure in the system. Useful life depends largely on the pipe material, but can also depend on soil conditions, wastewater constituents, and installation. When a pipe is in service beyond its useful life, the increasing costs of maintenance associated with a failing pipe will likely warrant replacement. Approximately 48,000 LF of pipe, or 30 percent, of the City s major collectors have a remaining useful life of 10 years or less and approximately 79 percent of the existing major collectors are expected to reach the end of their useful lives by the year The recommended projects related to the condition assessment are herein referred to as repair projects and together make up the recommended Repair Program, as shown in Table ES.1. The Repair Program is included in the Capital Improvements Plan in Chapter 8 of the Master Plan. In addition to the specific pipeline and pump station repair projects, a general pipeline repair program that allocates annual funding is also recommended as shown in Table ES.1. Other non-project recommendations, or those that can be completed as part of ongoing maintenance and collection system management, are listed as follows: Monitor for the effects of hydrogen sulfide at the Bay View, Bella Terra, Lilly Bay, Maple Street, Marylhurst, Palisades, and Robinson Point Pump Stations. If signs of deterioration are found, install hydrogen sulfide control equipment. Add a Loss-of-Redundancy Alarm to all pump stations. Add stainless steel anchor bolts to pump stations lacking (Melrose Pump Station). Inspect and clean the Lilly Bay Force Main. STEP Policies - Continue to update City policies pertaining to STEPs. CAROLLO ENGINEERS ES-4 DRAFT - October 18, 2012

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6 Table ES.1 Repair Program Project ID Project Description Diameter Length Cost Capital Improvement Phasing (in) (ft) ($) Short-Term ( ) Long-Term ( ) MAJOR COLLECTORS PROJECTS Downtown Trunk T-DWN-1 North Shore Road to Cabana Lane $150,000 $150,000 T-DWN-2 Cabana Lane 12 1,561 $419,000 $419,000 L4 Trunk T-L4-1 Lake Grove Swim Park to Railroad $170,000 $170,000 McVey Trunk T-MCV-1 Halinan St, Laurel St, Yates St, Ash St to Pacific HWY 10 2,154 $478,000 $478,000 T-MCV-2 Pacific HWY from Burnham Rd to McVey Ave; parallel to McVey Ave to Maple St 15 2,939 $978,000 $978,000 Riverfront Trunk T-RF-1 Furnace Street to Riverfront Trunk $76,000 $76,000 Blue Heron Trunk T-BH-1 Southshore Blvd from Lakeridge Rd to Blue Heron Rd 10 3,942 $875,000 $875,000 T-BH-2 1 Blue Heron Bay & Cardinal Dr 15 4,097 $1,363,000 $1,363,000 East Mountain Park Trunk T-EMP-2 1 End of T-EMP-1 to Boones Ferry Road 18, 24 4,523 $1,744,000 $1,744,000 T-EMP-3 Boones Ferry Road 12 5,434 $1,458,000 $1,458,000 Forest Highlands Trunk T-FH-1 Iron Mountain Blvd, Country Club Road 15 5,965 $1,985,000 $1,985,000 South Lake Trunk T- SL-1 Bryant Road $77,000 $77,000 Lakewood Trunk T-LW-1 South edge of Lakewood Bay $163,000 $163,000 CAROLLO ENGINEERS ES-6 DRAFT - October 18, 2012

7 Table ES.1 Repair Program Project ID Project Description Diameter Length Cost Capital Improvement Phasing (in) (ft) ($) Short-Term ( ) Long-Term ( ) L5 Trunk T-L $94,000 $94,000 Other Major Collector Repairs P-1 Other Major Collector Repairs - - $12,466,000 $1,115,000 $11,351,000 PUMP STATION PROJECTS Annual Pipeline Repair Program, $703,000 per year Pipeline Repair Program Cost $22,496,000 $5,624,000 $16,872,000 PS-1 Bay View, Lilly Bay, Maple Street Pump Stations Conversion To Submersible Pump Stations $1,328,000 $1,328,000 PS-2 Marylhurst Pump Station Replacement $1,826,000 $1,826,000 Pump Station Repair Cost $3,154,000 $3,154,000 ALL REPAIR PROJECTS All Repair Program Total Cost $25,650,000 $8,778,000 $16,872,000 All Repair Program Annual Cost $801,563 $1,097,250 $703,000 Notes 1. Includes a capacity improvement project within the extents of the project. See project details in Appendix K for location. CAROLLO ENGINEERS ES-7 DRAFT - October 18, 2012

8 ES.4 BASE FLOW ESTIMATION Estimating wastewater flow is important for understanding the current and future capacity requirements of the wastewater collection system. Wastewater flows are typically categorized into base flow and peak flows. Base flow, also called dry weather or sanitary flow, is defined as wastewater flow from residential, commercial, and industrial sources. Base flow is calculated when rainfall has little or no impact on flow volumes. Peak flows are caused by infiltration and inflow (I/I). I/I is storm water and ground water that enters into the collection system during wet weather and can result in flows significantly higher than base flow. In Lake Oswego, peak flows resulting from I/I are more than 10 times the base flow, indicating high amounts of I/I. As part of developing the design flows for the City s Lake Oswego Interceptor Sewer (LOIS), the City installed 35 temporary flow meters at strategic locations throughout the City in 2007 and The flow data from the LOIS flow-monitoring program were utilized to develop base flow estimates, for calibrating the collection system model, and for helping evaluate I/I impacts in individual sewer basins. Current base flows for each wastewater basin were estimated using current land use and land use flow factors. The City s current base flows were derived by calculating the areas of land currently contributing flow to the wastewater system. All properties currently within the City limits were assumed to be connected to the wastewater system. The current land use for these properties was based on data from the City s Geographical Information System (GIS) and Metro s Data Resource Center (DRC) taxlot information. LOIS flow monitoring data was incorporated to generate land use flow factors that represent the amount of flow produced by each type of customer. Future base flows were estimated by projecting the current base flows to the years 2020 (Short-Term), 2045 (Long-Term), and Build-Out. The Short-Term and Long-Term Base Flows were developed by increasing the current base flows according to anticipated rates of development in the City and surrounding areas as estimated from Metro s 2005 Transportation Analysis Zones (TAZ). Build-Out land use assumptions were based on the City s Comprehensive Plan and projected future developments per the City s planning department. The City is largely built-out with few large parcels of vacant land. Future growth is specifically anticipated in the Foothills Neighborhood (Riverfront and L1 Basins), and the Marylhurst Neighborhood. Base flows were estimated for each of the 22 sewer basins, for the total system, and at the Lake Oswego Meter at the Tryon Creek WWTP for 2010, Short-term (2020), Long-term (2045), and Build-out conditions. Table ES.2 summarizes the base flow estimation. CAROLLO ENGINEERS ES-8 DRAFT - October 18, 2012

9 Table ES.2 Summary of Base Flow Estimation Collection System Existing Base Flows (2010) (mgd) Short-Term Base Flows (2020) (mgd) Long-Term Base Flows (2045) (mgd) Build-Out Base Flows (mgd) Tryon Creek WWTP Lake Oswego Meter Flow to BES Flow to CWS Total System ES.5 HYDRAULIC MODEL DEVELOPMENT The limited hydraulic model previously developed for the LOIS project was updated and extended for the Master Plan. The model was converted and updated using MIKE URBAN, collection system modeling software developed by the Danish Hydraulic Institute (DHI). The LOIS model included the primary trunk sewers from each sewer basin, as well as the proposed interceptor in the lake. The updated collection system hydraulic model includes all of these pipe segments, and extends the trunks consistent with the scope of the planning effort and the master planning needs. The resulting pipes included in the model are herein referred to as major collectors. The model also includes three of the City s twelve pump stations: the Willamette, Bryant Road, and Marylhurst Pump Stations. The flow monitoring data collected as part of the preliminary design of the LOIS project was used for calibrating the model so that it more accurately predicts collection system s response to wet weather flows. Nineteen of the 22 sub-basins modeled met the established calibration criteria. The results of the calibration are consistent with other Northwest collection systems modeled in MIKE URBAN. Based on these results, the calibrated model is an appropriate tool for analysis of conveyance capacity for modeled storms, as well as a tool for aiding in I/I reduction planning. However, it is recommended that the City continue to update, expand, and improve the model as better flow monitoring data are collected. ES.6 PEAK FLOW ESTIMATIONS Peak flows were estimated using the updated model. The peak flows were estimated using two storm events: the 5-year, 24-hour and 25-year, 24-hour storm events. Peak flows resulting from these two storm events were determined for each sewer basin and at the Lake Oswego Meter at the Tryon Creek WWTP. Peak flows were estimated for 2010, Short-term (2020), Long-term (2045), and Build-out conditions. The City has high peak flows, and for the entire collection system, peak flows are approximately 10 times base flows. These high peak flows indicate that high amounts of I/I CAROLLO ENGINEERS ES-9 DRAFT - October 18, 2012

10 are entering the sanitary sewer system. Some individual sewer basins show a significantly more extreme response to wet weather conditions. An example is the Lakewood sewer basin, which has a peak flow that is nearly 30 times that basin s base flow. Such extreme ratios between base flow and peak flow typically indicate that there are improper storm water connections to the sanitary sewer and/or the collection system is in a deteriorated condition. The estimated peak flows are used to evaluate the capacity of the wastewater collection system for conveying current and future flows, to prioritize I/I reduction efforts, and to identify necessary wastewater collection system capacity improvements. Table ES.3 summarizes the current and projected peak hourly flows at the Lake Oswego Meter at the Tryon Creek WWTP and the entire system for 2010, Short-term (2020), Long-term (2045), and Build-out conditions. Table ES.3 Peak Flows from the 25-Year Storm 1 Collection System 2010 Peak Flow (mgd) 2020 Peak Flow (mgd) 2045 Peak Flow (mgd) Build-Out Peak Flow (mgd) Tryon Creek WWTP Lake Oswego Meter Flow to BES Flow to CWS Total System Notes: 1. Base flow at time of day when Peak Flow occurs. Based on basin diurnal curves. 2. As measured using the hydraulic model. Basins not included in calibrated model, thus peak flows were not developed from the model. ES.7 INFLOW AND INFILTRATION REDUCTION PROGRAM The Master Plan recommends an on-going program to reduce inflow and infiltration into the City s wastewater collection system. The City has exceptionally high inflow and infiltration as indicated by the ratio of Peak Flow to Base Flow, or peaking factor. Such high peaking factors result from improper storm water connections to the sanitary sewer, such as roof drains, foundation drains, and catchbasins, and/or pipes and manholes in a deteriorated condition. The impact of high I/I is significant and has a cost to the City. High peak flows result in the need for larger sewer pipes and pump stations. In addition, the City must pay for additional capacity at the Tryon Creek WWTP. High I/I can also cause sewer overflows and basement backups if the pipe, pump station, or treatment plant capacity is not adequate to convey the high flow. Sanitary sewer overflows are currently prohibited by the United States Environmental Protection Agency and the Oregon State DEQ. In 2007, the City signed a Mutual Agreement and Order (MAO) with DEQ to manage and reduce the potential for overflows, thereby protecting the City from ongoing enforcement of CAROLLO ENGINEERS ES-10 DRAFT - October 18, 2012

11 state and federal regulations. As part of its MAO with DEQ, the City undertook the planning, design, and construction of the LOIS. It should be noted that I/I reduction was assumed in the sizing of the LOIS and without an I/I Reduction Program, the LOIS does not meet the initial project capacity objectives. Discharges from the Tryon Creek WWTP are regulated through Portland s NPDES Permit Permit conditions have required the City to adopt and implement an Inflow and Infiltration Reduction Program. In 1999, the City prepared an I/I Reduction Program Plan to meet this requirement. An I/I Reduction Program is recommended to improve the condition of the collection system, reduce peak flows, and comply with the City s previous agreements to reduce I/I. Chapter 7 outlines the recommended I/I Reduction Program. The basins for the recommended I/I Reduction Program were prioritized to reduce peak flows contributing to the LOIS interceptor and meet the City s pipe conveyance capacity criteria. The recommended program is based on several assumptions about the effectiveness of I/I reduction techniques as reported by King County, Washington. Figure ES.3 identifies the I/I Reduction Targets for the basins. CAROLLO ENGINEERS ES-11 DRAFT - October 18, 2012

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13 ES.8 CAPACITY EVALUATION The capacity evaluation of the collection system and the proposed projects that correct capacity deficiencies result in two recommended programs: the Improvement Program, which addresses current capacity deficiencies, and the Expansion Program, which identifies infrastructure required to serve future customers where the system expands beyond its current configuration. The following summarizes the recommended Improvement and Expansion Programs. Improvement Program The Improvement Program includes the recommended I/I Reduction Program, as well as pipe and pump station capacity improvement projects. The I/I Reduction Program consists of performing Sanitary Sewer Evaluation Surveys (SSES ), installing permanent flow monitoring, implementing I/I Reduction Projects, and overall Program Administration. The cost estimates reflect these four components. It is anticipated that the costs of this program may be reduced through additional SSES and flow monitoring data, allowing a more targeted approach. Priority A Basin I/I reduction projects were developed meet the City s overflow criteria and are recommended to be implemented as soon as possible. It is assumed that the City will require at least ten years to implement the Priority A projects and achieve the I/I reduction targets for each basin. The Priority B projects are proposed to be initiated later in the planning period. The recommended I/I Reduction Program is summarized in Table ES.4 and in Chapter 7 of the Master Plan. The total program cost is reduced by cost estimates for pipe projects already planned in each basin, which are anticipated to alleviate I/I. The updated collection system hydraulic model was used to identify locations in the collection system where pipe conveyance capacity criteria were exceeded. Recommended projects for alleviating pipe capacity deficiencies were balanced with proposed I/I reduction in each wastewater basin. All recommended improvements to address capacity deficiencies are sized for build-out conditions. A summary of the capacity-related conveyance pipeline improvements projects, their associated costs, and recommended phasing are summarized in Table ES.5 and also included in the Capital Improvements Plan in Chapter 8 of the Master Plan. Table ES.5 also summarizes the recommended improvement projects to address capacity deficiencies at the City s existing pump stations. Other improvements to the existing pump stations include: Willamette and Foothills Pump Stations: Increase capacity concurrent with developing plans for the Foothills Development. Confirm capacity requirements concurrent with development. Marylhurst Pump Station: Implement temporary flow-monitoring at the pump station and just downstream of Marylhurst University. Melrose, Palisades, Phantom Bluff Pump Stations: Review historical pump run-time data to determine historical flows. Re-evaluate capacity requirements accordingly. CAROLLO ENGINEERS ES-13 DRAFT - October 18, 2012

14 Additionally, the following projects have also been included in the CIP as they require specific allocation of capital funding: Telemetry Feasibility Study & Implementation at Bryant Road, Marylhurst, and Willamette Pump Stations; Flow Data Tracking at all Pump Stations; Development of an Asset Management Program. Table ES.4 I/I Reduction Basin Target I/I Reduction (%) Estimated Program Cost Projects Identified as Conveyance Pipeline Improvements Net Project Cost Priority A South Lake 3 40 $1,078,000 $77,000 $ 1,001,000 South Lake 2 40 $4,764,000 $ - $ 4,764,000 McVey 25 $7,586,000 $1,456,000 $ 6,130,000 South Shore 1 25 $591,000 $257,000 $ 334,000 South Lake 1 40 $5,272,000 $ - $ 5,272,000 South Shore 2 25 $1,741,000 $ - $ 1,741,000 South Shore 3 25 $1,999,000 $ - $ 1,999,000 Canal B 25 $1,677,000 $1,258,000 $ 419,000 Total Priority A $24,708,000 $3,048,000 $21,660, Yr Annual Cost ( ) $ 2,166,000 Priority B West Mountain Park 25 $10,968,000 $475,000 $ 10,493,000 East Mountain Park 1 25 $6,661,000 $3,457,000 $ 3,204,000 Lakewood 25 $1,280,000 $163,000 $ 1,117,000 Marylhurst 10 $101,000 $ - $ 101,000 Blue Heron 15 $253,000 $ - $ 253,000 L3 15 $23,000 $ - $ 23,000 Riverfront 15 $33,000 $ - $ 33,000 EMP 2 15 $150,000 $ - $ 150,000 Total Priority B $19,469,000 $4,095,000 $15,374,000 Total Program Cost $44,177,000 $7,143,000 $37,034,000 CAROLLO ENGINEERS ES-14 DRAFT - October 18, 2012

15 Table ES.5 Improvement Program Project ID GENERAL PROJECTS Project Description Cost Capital Improvement Phasing ($) Short-Term ( ) Long-Term ( ) G-1 Asset Management Program $150,000 $150,000 G-2 Master Plan Updates ($300,000 each) $900,000 $300,000 $600,000 G-3 Priority A Basins - I/I Reduction Program $21,660,000 $17,328,000 $4,332,000 Priority B Basins I/I Reduction Program $15,374,000 $0 $15,374,000 CONVEYANCE PIPE PROJECTS General Project Cost $38,084,000 $17,778,000 $20,306,000 Diameter (in) Length (ft) Foothills Road Interceptor T-L1-1 Foothills Road to Tryon Creek WWTP $404,000 $404,000 South Shore Trunk T-SS-1 Near end of Lake Front Rd 12, $ 257,000 $257,000 Riverfront Trunk T-RF-2 George Rogers Park from Furnace St to Riverbend Condos East Mountain Park Trunk $391,000 $391,000 T-EMP-1 Parallel to Lakeview Blvd $255,000 $255,000 Downtown Trunk T-DWN-3 3rd Street from Evergreen Road to Lake Bay Ct $74,000 $ 74,000 T-DWN-4 3rd Street from Evergreen Road to waterfront $49,000 $ 49,000 Forest Highlands Trunk T-FH-2 Chandler Rd $17,000 $17,000 West Mountain Park Trunk T-WMP-1 Parallel to Del Prado Road 12 1,770 $475,000 $475,000 Pipeline Improvement Cost $1,922,000 $1,650,000 $272,000 CAROLLO ENGINEERS ES-15 DRAFT - October 18, 2012

16 Table ES.5 Improvement Program Project ID PUMP STATION PROJECTS Project Description Cost Capital Improvement Phasing ($) Short-Term ( ) PS-3 Willamette Pump Station Capacity Increase $663,000 $663,000 PS-4 Foothills Road Pump Station Capacity Increase $398,000 $398,000 PS-5 Telemetry Feasibility Study & Implementation $396,000 $396,000 PS-6 Flow Data Tracking $266,000 $266,000 Pump Station Improvement Cost $1,723,000 $1,723,000 Long-Term ( ) ALL IMPROVEMENT PROJECTS Improvement Program Total Cost $41,729,000 $21,151,000 $20,578,000 Improvement Program Annual Cost $1,304,031 $2,643,875 $857,417 CAROLLO ENGINEERS ES-16 DRAFT - October 18, 2012

17 Expansion Program The projects listed in Table ES.6 are recommended to meet the capacity requirements of future users and therefore define the Expansion Program. The table summarizes the capacity-related conveyance pipeline expansion projects, their associated costs, and recommended phasing. In general, the existing infrastructure was shown to have adequate capacity to serve most new service areas, with the exception of the Canal and Southwood Basins. In the Canal Basin, recommended improvements include increasing the size of the Canal Trunk and Childs Road Collector, and replacing the existing Childs Road pump station with a new pump station to serve properties in the Canal Basin near the Tualatin River as they connect to the wastewater system. In the Southwood Basin, increasing the size of the Southwood Trunk is recommended. Table ES.6 Expansion Program Project ID Project Description Diameter Length Cost Capital Improvement Phasing (in) (ft) ($) Build-Out (2046+) PIPE PROJECTS Canal Trunk T-CAN-1 Oswego Canal upstream of Bryant Road Pump Station 21 2,845 $1,258,000 $1,258,000 P-CAN-1 Childs Road 12 1,570 $421,000 $421,000 Southwood Trunk P-SW-1 Bangy Road 10 1,864 $414,000 $414,000 Pipeline Expansion Cost $2,093,000 $2,093,000 PUMP STATION PROJECTS PS-7 New Canal Basin Pump Station $984,000 $984,000 Pump Station Expansion Cost $984,000 $984,000 Expansion Program Total Cost $3,077,000 $3,077,000 CAROLLO ENGINEERS ES-17 DRAFT - October 18, 2012

18 ES.9 CAPITAL IMPROVEMENTS PLAN The capital improvements plan (CIP) resulting from the collection system evaluation will provide the City with a guideline for the planning and budgeting of its wastewater system. The CIP combines the recommended Repair, Improvement, and Expansion Programs. Chapter 8 of the Master Plan summarized the cost estimates and schedule for the recommended improvements. It is important to note that this CIP does not include costs for maintenance or improvements of the entire wastewater collection system. This Plan was developed to focus on the City s major collectors (as defined in Section ES.5) and pump stations as these are the most critical wastewater infrastructure. Future master plans will likely include evaluation of the small wastewater pipelines within each basin. Table ES.7 summarizes the recommended Repair, Improvement, and Expansion projects presented above. As seen in the table, the CIP recommends investing $29.9M in the wastewater system in the Short-Term. This high cost includes several critical programs, including an I/I Reduction Program required for reducing peak flows, capacity improvements to reduce surcharging manholes, and repair projects to address aging infrastructure. The annual Short-Term cost for all recommended programs is approximately $3.7M per year from 2013 to For the Long-Term, the CIP recommends an additional $37.5M be invested to continue these programs. The annual Long-Term cost is approximately $1.6M per year from 2021 to Table ES.7 Capital Improvements Plan Summary Capital Cost ($) Short-Term ( ) Capital Improvement Phasing ($) Long-Term ( ) Build-Out (2046+) REPAIR PROGRAM Total Cost $25,650,000 $8,778,000 $16,872,000 N/A Annual Cost $801,563 $1,097,250 $703,000 N/A IMPROVEMENT PROGRAM Total Cost $41,729,000 $21,151,000 $20,578,000 N/A Annual Cost $1,304,031 $2,643,875 $857,417 N/A EXPANSION PROGRAM Total Cost $3,077,000 N/A N/A $3,077,000 Annual Cost N/A N/A N/A N/A ALL PROGRAMS Total Cost $70,456,000 $29,929,000 $37,450,000 $3,077,000 Annual Cost $2,105,594 $ 3,741,125 $ 1,560,417 N/A Figures ES.4, ES.5, and ES.6 show the project locations of the short-term, long-term, and Build-out recommended projects. CAROLLO ENGINEERS ES-18 DRAFT - October 18, 2012

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22 ES.10 SUMMARY The City s Wastewater Collection System Master Plan provides the City with a program to meet its goals and objectives for wastewater service for more than 30 years. It provides a current inventory and analysis of the City s wastewater collection system infrastructure condition and capacity. The City s wastewater collection system is aging and showing signs of deterioration. High peak flows were measured during flow monitoring and because of infiltration and inflow, large storm events will result in more flow than the collection system has capacity for. These high peak flows are indicative of a collection system that has improper storm water connections to the sanitary sewer and/or the wastewater collection system is in a deteriorated condition. The Plan recommends that the City embark in an ongoing program to rehabilitate the sewer system and reduce infiltration and inflow. In addition, there are pipelines that have reached the end of their remaining useful life and need to be rehabilitated or replaced. These improvements to the existing system are necessary to meet the City s level of service standards, to protect the City s investment in LOIS, and to cost-effectively serve new customers as the City expands in the future. If the recommended I/I Reduction Program is not implemented, peak flow will continue to increase over time as the collection system continues to deteriorate, increasing the potential for more frequent sewer system overflows and increasing the treatment capacity requirements at the Tryon Creek WWTP. The proposed Capital Improvement Plan (CIP) identifies and prioritizes the repair, improvement, and expansion projects to the City s conveyance piping and pump stations. Many of the improvements are proposed to be completed by 2020 to rehabilitate or replace facilities that have exceeded their useful life and to meet the City s capacity design criteria. Implementation of the proposed CIP will take a focused and on-going investment by the City. As the City implements this program, it will be necessary for staff to balance capacity improvements driven by peak flows with implementation of the recommended I/I Reduction Program. The updated and calibrated collection system model will be a useful tool for continued evaluation of the improved and modified collection system. CAROLLO ENGINEERS ES-22 DRAFT - October 18, 2012