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Task 2.1 Site Assessment/Preliminary Design <br />The Consultant will: <br />1. Review the City's existing as -built and GIS information. <br />2. Develop contributing area basin delineations to proposed treatment site. <br />3. Preform hydrologic modeling and design flow documentation. <br />4. Develop preliminary treatment facility sizing and facility costs <br />5. Develop recommended facility type and location. <br />Assumptions: <br />• The City will provide available data for this project including as -built drawing information for <br />storm, water, and sewer systems. <br />• The Consultant will review up to three potential facility locations along 31d Ave SE for selection <br />of single preferred facility location. <br />• Basin delineations will be based on City provided GIS data and field verifications. <br />• Design flows will be based on hydrologic modeling using the Western Washington Hydrologic <br />Model (WWHM) <br />• Treatment facility will provide a minimum Basic Treatment standard, but potential for Enhance <br />Treatment will be evaluated. Enhanced treatment will be provided if feasible. <br />• Up to three types of proprietary treatment systems will be evaluated per site constraints and cost <br />comparisons. <br />• Up to three preliminary water quality layout exhibits will be developed based on GIS data. <br />• A pretreatment facility will be provided upstream of the water quality treatment facility. <br />• Conveyance capacity of proposed pipes and downstream connection pipe will be evaluated using <br />Rational Method and Manning's flow -flow analysis. <br />• Backwater analysis using SWMM will not be required. <br />Deliverables: <br />• Basin Delineation Figure (PDF). <br />• Proposed water quality system exhibits, up to three (PDF). <br />Tasks 3.4 Preliminary Design Report <br />The Design Report will consist of the following elements per Ecology's "Design Deliverables for <br />Stormwater Projects with Ecology Funding": <br />• Introduction <br />• Basin Description <br />• Site Description <br />• Minimum Requirement/Core Element Analysis <br />• Alternatives Considered <br />• Design Analysis <br />• Quantify the Water Quality Benefit <br />• Engineer's Opinion of Probable Cost <br />• Proposed Schedule <br />City of Everett <br />3rd Ave SE Water Quality Treatment Page 5 of 10 <br />