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Exhibit A LL <br /> FY <br /> Subtask 620 — Snohomish River Outfall Preliminary Design <br /> Objective <br /> Develop a preliminary (30%) design of the stormwater discharge outfall to the Snohomish River <br /> based on the conceptual design recommendations from Subtask 610. <br /> Consultant Services <br /> 1. The stormwater conveyance outfall design will evaluate and establish concept design of: <br /> a. Bank protection and erosion protections <br /> b. Scour and channel protections <br /> c. Conveyance system protections from the Snohomish River <br /> 2. Prepare a No-Rise analysis for the proposed outfall <br /> a. Obtain effective hydraulic model from FEMA. <br /> b. Using FEMA effective model, prepare a duplicate effective, corrective effective and/or <br /> existing condition, and proposed condition open channel hydraulic model of the <br /> Snohomish River using 1 D HEC RAS analysis at the proposed outfall location. <br /> c. It is anticipated that hydraulic modeling sections will be provided for up to 700 feet <br /> upstream and 700 feet downstream as measures along the approximate center of the <br /> Snohomish River. <br /> 3. Prepare a draft technical memorandum to document the conceptual outfall location and <br /> recommended design improvements. <br /> 4. Prepare preliminary (30%) design drawings for the stormwater outfall facilities design. <br /> 5. Prepare an Engineer OPCC (AACE Class 3) for the stormwater outfall facilities. <br /> 6. Prepare for and attend a meeting with City staff for up to two (2) hours to present the draft <br /> preliminary design memorandum outfall design and recommendations. The meeting will be <br /> conducted via MS Teams (or other web-based virtual platform) and up to four (4) consultant <br /> staff may attend. <br /> Client Responsibilities <br /> 1. Schedule meetings with key City staff in attendance. <br /> 2. Complete review of meeting notes and decision log within seven (7) calendar days. After <br /> this time, the notes and decision logs will be finalized and archived as per the project record. <br /> 3. Coordinate City reviews and provide consolidated, conflict-resolved review comments within <br /> three (3) weeks following submittal. <br /> 4. City will address easements or acquisitions necessary for the facilities. <br /> Assumptions <br /> 1. Outfall pipe material selection and hydraulic modeling of the conveyance system between <br /> the stormwater treatment facility and the discharge outfall will be provided under Task 400. <br /> 2. Preparation of the preliminary (30%) design drawings for the recommended stormwater <br /> discharge outfall facilities will be developed under Task 610. <br /> Lexington Avenue Storm Drainage Improvements Preliminary Design Scope of Services <br /> 19 <br />