HDR Engineering Inc. 12/16/2022 - Laserfiche WebLink

City of Everett – Replacement of Reservoir 3 4 Scope of Services 7. Quality assurance/quality control plan (PDF format). 8. Documentation of quality reviews. Task 200 – Preliminary Design Report Task Objective Develop alternatives for replacement reservoirs, identify a preferred alternative, and prepare the Project Report for the proposed water storage improvements for submittal to the Washington State Department of Health (DOH). Consultant Services 1. Perform system-wide hydraulic analysis to evaluate the operational, equalization, fire storage volumes and impacts to available fire flow and system pressures based on the following conditions: a. Increasing the height of reservoir above existing operating level to increase operating pressure b. Impacts of additional storage beyond the existing 20 MG. c. Operating system impacts of reduced storage capacity during interim condition when Phase 2 is under construction to determine if Phase 1 reservoir construction needs to be increased beyond 10 MG. d. Impacts of raising the Reservoir 3 overflow elevation on the water system including City’s and Alderwood Water and Wastewater District (AWWD) Booster Pump Stations. e. Summarize analysis results into a draft Hydraulic Analysis technical memorandum (TM) for City review. 2. Prepare for and conduct a Hydraulic Analysis Workshop with the City to review the hydraulic analysis findings and determine the appropriate operating and storage conditions needed for each design phase. The Consultant will prepare and provide a comment log in Microsoft Excel format to track comment responses. Update TM based on City comments and Hydraulic Analysis Workshop and issue final TM. 3. Based on the direction received from the City from the Hydraulic Analysis Workshop, HDR will proceed with preparing a draft Preliminary Design Report (PDR) outlining the following: a. Determining locations, sizes, and configurations of multiple reservoirs within the City’s current property b. Evaluating alternative construction methods for the replacement reservoirs including circular and rectangular concrete reservoir configurations. c. Associated site / civil facilities, including interconnecting pipes and valves, and landscaping including features to minimize aesthetic impacts to neighbors. d. A separate standalone Stormwater Memorandum will be developed for both phases of the project to define stormwater management considerations (detention, treatment, conveyance). This memorandum will be appended to the PDR. e. Construction phasing requirements. f. Construction access and staging including spoils management. g. Geotechnical recommendations for reservoir excavation to avoid impacts to existing reservoir, new Phase 1 reservoirs, and adjacent utilities, structures, and homes. h. Seismic design recommendations. i. Reservoir foundation design requirements.