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6 • <br /> 6. Based on the complexity and feasibility of performing long-term model simulations through <br /> out the-entire collection system, make a recommendation from the following-options: 1) <br /> continuing to use the long term rainfall time series;-2) consolidating the key historical storm <br /> events into an abbreviated rainfall time series; 3) using specific historical events; or 4) <br /> developing synthetic storm events for subsequent use in evaluating the level of service <br /> throughout the remainder of the collection system. <br /> 7. Establish the level of service for the sewer collection system basins throughout the entire <br /> service area. The level of service assessment within basins will be refined for areas that <br /> have been identified through field observations as areas with potential level of service <br /> capacity. <br /> City Responsibilities <br /> 1. Provide rainfall data from City and SFE Global rain.gages. <br /> Assumptions <br /> 1. The City's historical rainfall data includes 50 years of hourly data and short duration (5 to 15 <br /> minutes) data from recently installed rain gages through the service area. <br /> 2. Level of service of the collection system will be characterized a less than 5 year LOS, 5 to <br /> 20 year LOS, and greater than 20 year LOS. <br /> 3. Up to four meetings with the City will be held to 1) review available data, 2) review rainfall <br /> characteristics in the local area and proposed rainfall time series, 3) review draft LOS <br /> analysis results,and 4) review selected design storm events or rainfall approach for <br /> subsequent analysis. <br /> Deliverables <br /> 1. 'A draft and final technical memorandum recommending a long-term model simulation rainfall <br /> time series for use in analyzing the collection system. Multiple time series maybe <br /> recommended depending upon evaluation of rainfall patterns across the service area. <br /> 2. Summary of historical rainfall events or design events to be used for subsequent system <br /> analysis. <br /> 3.. A draft and final technical memorandum describing the process used to determine levels of <br /> service and the resulting level of service ratings for sewer drainage basins within the <br /> collection system. <br /> Task 700 — Update Existing Plan Chapters <br /> Objective <br /> To update useable sections of the existing sewer plan to meet WAC 173-240-050 requirements. <br /> HDR Services <br /> 1. Update the following existing plan sections with currently available information: <br /> A. Executive Summary (pending development of the remaining revised sewer plan <br /> chapters) <br /> B. Chapter 1. Introduction <br /> City of Everett Comprehensive Sewer Plan Update 418 Scope of Services April 2011 <br />