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Scope of Services <br /> Continued <br /> e. Coordinate with the City to install up to two flow monitoring stations that can be 1 <br /> used to calibrate the model,potentially at a leaping weir or a lift station. <br /> 2. Updating Current and Pre-Existing Sewer System <br /> a. Pre-2008 sewer system before Sewer I was built.The system before the Sewer I <br /> Project was built and modifications of the 24-inch sewer line in Rockefeller <br /> Avenue between 136 and 14th Street <br /> b. Pre-2008 sewer system before Sewer I was built,but with the 24-inch bypass <br /> sewer improvements proposed by Providence Hospital at the time,but never <br /> completed. <br /> c. The current sewer system with the all planned PEMC expansions <br /> completed/built-out. <br /> d. Update the current 17th Street Interceptor sewer system to include any elements <br /> verified by field surveying the 17th Street Interceptor and connecting think lines <br /> for capacity determination;this will include verifying that the lift stations are <br /> correctly represented in the model. <br /> e. Update and verify the current Broadway Interceptor systems and connecting <br /> trunk lines for capacity determination;this will include verifying that the lift <br /> stations are correctly represented in the model. <br /> 3. Evaluate Alternative Improvements Scenarios <br /> The following sewer system improvement alternatives will be evaluated: <br /> a. Improvements to the 17th Street Interceptor system to increase its capacity to <br /> receive additional flow from the Phase 1 improvements and convey it <br /> downstream. <br /> b. Improvements to the Broadway Trunk system to increase its capacity to receive <br /> additional flow from the Phase 1 improvements.Also to evaluate the function of <br /> the existing leaping weir at 17th Street and Broadway and to determine if an <br /> alternative method of flow diversion is preferable. <br /> c. Improvements involving PEMC existing facilities,which may include: deep <br /> infiltration (injection wells), surface runoff overflow from PEMC system to <br /> existing injection wells or streets, flood storage in PEMC parking garage, <br /> detention,PEMC overflow piped to different system,and overflow to wetland. <br /> d. Improvements involving PEMC future facilities which may include onsite <br /> stormwater detention,LID (Low Impact Development) measures or other <br /> methods to minimize offsite runoff. <br /> e. Improvements involving an overflow pipe to the Snohomish River CSO <br /> regulator. <br /> f. Improvements involving additional separated sanitary and storm sewer systems. <br /> g. Sewer system improvements using backflow preventers to protect homes in low <br /> lying areas, areas subject to backwater surcharging,and recommend locations <br /> where they should be used. <br /> City of Everett—North Everett Combined Sewer System Evaluation 7 <br /> otak <br /> K:\project\31500\31520\Contract\Amendll_NAreaFlooding\31520 Everett Sewer Amendment 1 Scope082510.doc <br /> 9 <br />