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Scope of Work <br />Task 1: Research and Site Reconnaissance <br />JS&TM will provide preliminary engineering services to collect and review existing background data. Data collection <br />includes right-of-way documents, existing utilities plans, soils, and geologic information, "as -built" construction <br />drawings for the lake, park and existing nearby utilities, existing hydraulic and master plans of drainage, irrigation <br />plans, previous project reports, and proposed development plans. Afield reconnaissance investigation of the project <br />study area will be performed. The field investigation will include an onsite meeting with COSA Public Works staff to <br />get input on observed issues with the lake, discuss objectives, and discuss needs for improved maintainability of the <br />lake facilities. Our research will also include review of available city records regarding water usage of the lake, power <br />consumption of the lake pumps and aerators, lake maintenance records (algae removal, fish kills, wildlife issues, etc.). <br />1S&TM will also perform field inspections of the existing facilities to assess the current condition of each component <br />system of the lake. This will include assessing the current condition of the following lake facilities: <br />• lake liner (obtain in -situ liner samples) <br />• lake wall <br />• recirculating stream liner system <br />• existing pumps <br />• lake skimmers <br />• lake fill control valve <br />• accessible aeration equipment <br />• existing pump vaults and electrical panels and controls <br />• lake perimeter landscape <br />• lake access paths <br />• fishing/angling facilities <br />• signage <br />• seating areas <br />• trash receptacles <br />• water quality control facilities <br />• maintenance access provisions <br />1S&TM subconsultant (Converse Consultants) will identify and document the historic groundwater table using the <br />USGS Water Data Website, the California Department of Water Resources SGMA Data Viewer Website, and historic <br />groundwater information from USGS Water Supply Papers from the early 1900's. Converse Consultants will provide <br />recommendations for future groundwater elevation beneath the site based on nearfield wells and trends. Converse <br />Consultants will obtain 2-3 soil samples under the guidance of 1S&TM and provide sieve analysis of soil samples in <br />general accordance with ASTM Standard D6913. <br />1S&TM will prepare a water balance analysis for the lake system accounting for lake inputs and withdrawals to <br />determine the expected lake water use compared to actual water usage. This analysis will provide an accurate <br />assessment of the condition of the existing lake liner. The water balance accounting will account for the following <br />water inputs and withdrawals: <br />• direct precipitation <br />• precipitation runoff inflow <br />• evaporation <br />Thornton Park Lake Circulation Study and Renovations Page 8 <br />