WHEREAS, the Board has previously so adopted a wastewater supply system comprehensive plan, and

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1 LAKEHAVEN WATER AND SEWER DISTRICT King County, Washington Resolution No A RESOLUTION of the Board of Commissioners of the Lakehaven Water and Sewer District, King County, Washington, adopting a general comprehensive plan for a wastewater supply system. WHEREAS, the Board of Commissioners is required, pursuant to R.C.W , to adopt a general comprehensive plan before ordering any improvements to the wastewater system or submitting to vote any proposition for incurring indebtedness for such improvements, and WHEREAS, the Board has previously so adopted a wastewater supply system comprehensive plan, and WHEREAS, the staff and consulting engineers have developed an updated general comprehensive plan for the wastewater supply system to replace the existing comprehensive plan, and WHEREAS, the Board having reviewed the same and believing that the plan meets the present and future needs of the District and its customers: NOW, THEREFORE, BE IT RESOLVED as follows: 1. The Board of Commissioners hereby adopts, as the general comprehensive plan for the wastewater supply system, the "", prepared by BHC Consultants, a true and correct copy of which is attached hereto as Exhibit "A" and is incorporated by reference herein. 2. Staff is hereby authorized and directed to submit the 2015 Wastewater System Comprehensive Plan to the appropriate county and city legislative authorities, and any regulatory agencies with jurisdiction, for approval. 3. The effective date of the for general purposes shall be the date upon which final approval is granted by the last legislative and/or regulatory body required to approve the comprehensive plan pursuant to statute. Upon the effective date, all prior comprehensive plans and amendments thereto shall be superseded by the comprehensive plan adopted herein. The effective date for purposes of including facilities referenced or described in the in the District's Resolution No Page 1

2 Capital Facilities Charges, shall be the date of the Board of Commissioners' adoption of the plan as set forth below. ADOPTED by the Board of Commissioners of Lakehaven Water and Sewer District, King County, Washington, at an open public meeting this 13 day of April, ATTEST: President and Commiss oner Yea Nay Abstain Vice President and Commissioner Yea Nay Abstain Secretary and Commissioner Yea Nay Abstain Commissioner Yea Nay Abstain Commissioner Yea Nay Abstain Approved as to form: General Counsel Resolution No Page 2

3 EXHIBIT 'A' Section ES Executive Summary This Comprehensive Wastewater System Plan (Plan) is a summary of the conclusions and findings completed by 's (District) staff and with the assistance of BHC Consultants, LLC in analyzing the District's existing wastewater collection and treatment systems. The Plan updates and supersedes the District's previous (2009) Comprehensive Wastewater Plan and has been prepared in accordance with all applicable regulatory Determine requirements. the adequacy The of primary the existing goals wastewater of the planning collection effort and were treatment to: system to meet the current and projected needs of Lakehaven's customers in accordance with all state, Develop federal recommendations and local regulations, for system as well improvements as current industry which standards. meet the wastewater collection and treatment system needs in an environmentally conscious manner, all while Identify protecting potential public mechanisms health and welfare. for funding recommended studies, improvements and other recommendations of the Plan. A State Environmental Policy Act (SEPA) Checklist and determination of non-significance (DNS) has been prepared for this Plan. The District anticipates this Plan does not have probable significant adverse impacts on the environment in accordance with the DNS under WAC (2). The SEPA Checklist and DNS are included in Appendix D. This Plan is required to meet state, county, and local requirements. The District will submit this plan to the Department of Health (DOH), the Department of Ecology (DOE), King County, adjacent utilities, and local governments as part of the Agency Review process. See Appendix B for the Comment Letters. The Adopting Resolution will be included in Appendix A, upon Plan approval by the Board of Commissioners. The following is a summary of the key elements of the planning process and sections of the Plan: ES.1 Introduction This section presents an overview of the study, history and objectives of the District, and a summary of the rules and regulations which govern the operation of the District and the development of the Comprehensive Plan document. ES.2 Basic Planning Data currently serves within the corporate limits of eight jurisdictions. The existing sewer service area identified in the Plan is not coincidental with the District's corporate boundary, but efforts continue to provide the most feasible consistency between the two boundaries as possible. Growth Management Act planning has established an Urban Growth Area (UGA) within which urban levels of service are to be provided in a timely and reasonable manner by. The entire corporate boundary of the District is within the UGA and Lakehaven is therefore responsible for planning accordingly. March 2017 ES-1 BHC Consultants, LLC

4 ES.3 Demographics Population and employment forecasts are based on the adopted land use plans of the various jurisdictions within which the District operates. For additional specific information on planning within a particular service area, it is recommended that the reader refer to the Comprehensive Plans provided by that jurisdiction. The future demographics were estimated using growth projections provided by the Puget Sound Regional Council (PSRC), King County, City of Federal Way and each jurisdiction within the Study Area. They are presented by drainage basin to allow for evaluation of the system and consideration of future improvement alternatives. In 2014, there were an estimated 132,600 residents and 33,350 employees within Lakenhaven's Sewer Service Area (SSA). Population has increased slightly above what was projected in the prior Plan. The previous Plan forecasted a population of 126,410 in the year The population is expected to be accelerated by changes in the City of Federal Way's zoning code to allow for more dense development and redevelopment to occur within the City, particularly in its Downtown Core. The population is projected to increase to nearly 144,500 by 2020, and almost 149,300 by the year Employment is expected to increase to more than 36,660 by 2020 and more than 40,500 by Some areas of the SSA remain unserved, particularly in the southeast, but plans to expand to unsewered areas as on-site systems become less viable to maintain and/or new development occurs is anticipated over the next 20 years and beyond. ES.4 Flow Projections Section 4 of this Plan discusses current and projected flows for the six major drainage basins identified in this Plan. Average base sanitary flow for all customers in Lakehaven is currently (2012) estimated at 6.32 MGD, and is expected to increase to nearly 6.71 MGD by 2020, and potentially up to MGD at full development (Buildout). Peak flows, including infiltration and inflow (I & I), are estimated at 17 MGD in 2012, 19 MGD by 2020, and nearly 28 MGD at Buildout. All calculated flow numbers referenced within this section were obtained from Table 4-8. ES.5 Existing Wastewater Collection System The existing collection system consists of approximately 325 miles of sanitary sewer pipes, 8,984 manholes, 28 pump stations, five siphons and two secondary wastewater treatment facilities. The system has been constructed over a number of years, and from a wide variety of materials, as dictated by development trends in the area. The system is divided into six primary basins and 56 smaller sub-basins. The two largest basins, Lakota and Redondo, flow to the District's wastewater treatment plants. The remaining basins currently discharge to other utilities for treatment and disposal. ES.6 Collection System Recommended Improvements Analysis of the collection system was accomplished with a computer modeling system using the design criteria established in the Plan. Primary issues resulting from analysis of the collection system were related to normal renewal and replacement programs, I & I control in the older areas of the system (especially Redondo), and capacity issues related to various growth scenarios. Collection system improvement projects identified in the Capital Facilities Plan are representative of these findings, as well as extension of service to currently unsewered areas. One particular challenge of this plan was to analyze the Downtown Core of Federal Way, which March 2017 ES-2 BHC Consultants, LLC

5 may see large increases in population and employment resulting from the City's Comprehensive Plan revised in Major recommended improvements for the collection system are primarily centered around Lakehaven's desire to treat as much sanitary flow within its corporate boundaries as feasible. The District has made significant progress to provide back-up power at all pump stations since the previous Plan. Further upgrades are discussed and budgeted for in the Capital Improvement Plan. ES.7 Treatment Facilities The Lakota Plant was constructed as a primary treatment plant in 1967 and upgraded to secondary treatment in The Lakota Plant was designed for a peak month flow of 10 mgd and a peak hour flow of 22.2 MGD. The Redondo Plant was constructed as a primary treatment plant in 1962 and upgraded to secondary treatment in The Redondo Plant was designed for an annual average flow of 5.6 MGD and a peak hour flow of 13.8 MGD. The Redondo Plant has limited room for expansion at its current site, while Lakota has room for expansion when dictated by growth and development. ES.8 Recommended Treatment Facility Improvements The recommended improvements fall into two categories, general improvement requirements. and capacity expansion requirements. General improvements are those needed to improve individual processes and provide improved control of the plants. Capacity improvements are those needed to accommodate future wastewater flows, particularly peak hour and month flows. Some capacity improvements, particularly at the Redondo Treatment Plant, may be avoided if ongoing efforts to study and reduce I & I are successful. Alternatively, estimated cost for added collection and treatment capacity may be more cost effective and should achieve more reliable results. Lakehaven continues to study the effects of their successful water conservation efforts on the treatment process, and have evaluated options for re-routing flows from the Redondo collection system to the Lakota system in order to optimize the treatment process. At this 2016 date, re-routing flows is not anticipated to occur in the near term of the next 6 years. ES.9 Hydraulic Capacity Analysis Analyses were performed using data during which period annual average day wastewater flow to Lakota was 5.4 MGD and to Redondo was 2.8 MGD. Maximum day flows for 2013 were 8.2 MGD at Lakota and 7.2 MGD at Redondo. Hydraulic Capacity Analysis Average day flows for the hydraulic analysis formed a key component for model calibration. Hydraulic capacity was evaluated dynamically for peak day flow with a derived diurnal curve to estimate peak hour conditions for the Lakota and Redondo Basins. Lacking measured flows to calibrate a hydraulic model, capacities in the four smaller basins were evaluated with an Excel spreadsheet to compute peak hour flows by basin using Lakota and Redondo unit flows. Treatment capacity allowed by the NPDES Permit at both plants is 10.0 million gallons per day (MGD) at Lakota and 5.6 MGD at Redondo. Based on the permit capacity trigger of 85 percent of permitted flow for three consecutive maximum months, Lakota treatment facility is currently operating at about 59 percent of hydraulic capacity and Redondo treatment facility is currently operating at about 68 percent of hydraulic capacity. ES.10 Lakota Process Capacity Analysis Analyses were performed on 2011 to 2013 data and individual process unit capacities were compared to Washington State Ecology Department design criteria. Primary treatment comprises screening (22.0 MGD peak hour capacity), grit removal (22.9 mgd peak hour capacity) and primary clarifiers (22.4 MGD peak hour capacity) and has adequate capacity. Grit March 2017 ES-3 BHC Consultants, LLC

6 and primary scum removal need improvement to protect and optimize downstream processes. Secondary treatment comprises aeration basins, secondary clarifiers (22.2 MGD peak hour) and UV disinfection (22.2 MGD peak hour). Solids treatment comprises thickening, digestion and dewatering. An overview of capacity by unit process is summarized in Table 8-5. The table includes physical and operating parameters for each process. Operating parameters are shown based on the design flows and loads, current flows and loads, projected 2020 flows and loads and the projected build-out flows and loads. The plan has addressed some of the treatment process components that may require capacity upgrades in the near future like the screens, blowers and raw activated sludge (RAS) pumps. A more detailed assessment of the treatment process components capacity limitations during the six-year program can be found in Section 8. ES.11 Redondo Process Capacity Analysis Analyses were performed on data and individual process unit capacities were compared to Washington State design criteria. Primary treatment comprises screening (13.8 MGD peak hour capacity), grit removal (14.5 mgd peak hour capacity) and primary clarifiers (12.1 MGD peak hour capacity). Secondary treatment is comprised of aerating trickling filters, secondary clarifiers and UV disinfection. Secondary capacity, and consequently overall process capacity, is limited by clarifier capacity (10.1 MGD peak hour) and UV disinfection capacity (13.8 MGD peak hour). Solids treatment comprising digestion and dewatering has adequate capacity. Limited thickening is achieved in the process tanks rather than a separate thickening process. An overview of capacity by unit process is summarized in Table 9.4. The table includes physical and operating parameters for each process. Operating parameters are shown based on the design flows and loads, current flows and loads, projected 2020 flows and loads and the projected build-out flows and loads. The plan has addressed some of the treatment process components that may require capacity upgrades in the near future like the, screens, grit removal, primary and secondary clarifiers and pumps. A more detailed assessment of the treatment process components capacity limitations during the six-year program can be found in Section 9. ES.12 Biosolids Dewatered biosolids cake from both plants, stabilized to Class B quality in the digesters, is trucked to Eastern Washington to be utilized by farmers on their crop lands. Metals content in the biosolids has been consistently well below EPA regulatory limits for land application and is currently below EPA limits for "clean" biosolids. ES.13 Water Reuse Lakehaven has evaluated the feasibility of municipal wastewater reuse to replenish ground water resources extracted for potable water use. As a component of the District's water use efficiency programs, a program for the reuse of treated wastewater was prepared. This plan was first prepared in 2005 and has since been updated to reflect the most recent regulatory requirements and water reuse opportunities. The 2015 Comprehensive Water System Plan Section 6 provides an evaluation of the Lakota WWTP feasibility of wastewater reuse. Landscape irrigation and groundwater recharge are the two potential reclaimed water uses identified within the District. Future reclamation treatment facilities would be located at the Lakota VVVVTP and possibly the Redondo WWTP, if implemented. ES.14 Financing Implementation Several typical funding options are available to the. These include the following: March 2017 ES-4 BHC Consultants, LLC

7 State and Federal Grants and Loans; Bond Financing, both General Obligation Bonds and Revenue Bonds; Privatization; Pay-As-You-Go; Capital Reserve Funds; Development Based Funding; Customer Service Rates and Connection Fees. An appropriate funding mix is needed by the District to finance the proposed Capital Improvement Plan summarized in Section 11 of this Plan. Given the current (2015) economic climate, the District should continue to aggressively pursue government loan funding, economic recovery funding as it becomes available, and build reserve funds to finance scheduled system repairs and upgrades. The District should continue to evaluate the benefit of inter-local contracts with Agencies who may share in the cost of the improvements. March 2017 ES-5 BHC Consultants, LLC