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REGIONAL GROUNDWATER FACILITIES PROJECT <br />FEASIBILITY STUDY <br /> <br /> 8 Zone 7 Water Agency <br />December, 2025 <br /> <br />The well capacity estimates provided in this study, and hence the overall project yield, should be <br />considered best estimates at this time based on installation and testing of relatively small diameter test <br />wells. The final full-scale production well yields and overall project yield may vary by several hundred gpm <br />more or less than the test well based estimates provided in this feasibility study. Production well yields <br />will be a function of multiple variables (e.g., specific capacity and well efficiency) that may vary between <br />test well drilling and production well drilling. The amount of project yield above the baseline amount <br />allocated to City of Pleasanton (and hence, available to Zone 7) cannot be confirmed until production <br />wells are installed and tested. <br />2.1.3. Well Pump Sizing <br />Preliminary well pump motor sizing for each proposed well was developed using estimated design <br />parameters (including but not limited to: production flowrate ranges, deepest anticipated pumping water <br />levels, and maximum assumed discharge pressures) in order to estimate brake horsepower (bhp), nominal <br />well pump motor size requirements, and electrical input power for each production well site. Calculations <br />assumed pumping water levels at the top of the well screen, design flow rates during wet/average/dry <br />years, an estimated discharge pressure of 100 psi at the wellhead, an assumed bowl efficiency of <br />approximately 75 percent. <br />Preliminary estimates of brake horsepower requirements for each well pump are based on the preliminary <br />assumptions described above and are therefore subject to refinement as additional production well test <br />data, hydraulic modeling results, and other information affecting lift and flow become available. Using <br />these assumptions, estimated brake horsepower requirements are on the order of approximately 250 hp <br />for the Del Prado well and approximately 700 hp for the Tennis Park and Hansen Park wells. Actual brake <br />horsepower requirements and corresponding nominal motor sizes will depend on factors including final <br />dynamic range of discharge head conditions, production well specific capacity, well efficiency, and <br />installed pump configuration. Accordingly, the brake horsepower and motor sizing values presented <br />herein are preliminary and will be confirmed and refined through full-scale production well installation <br />and performance testing. <br />2.2. Modeling of Future Groundwater Levels <br />Three model scenarios were developed by Zone 7 and LSCE for simulation of future groundwater level <br />conditions with operations occurring at two or three new test well sites. The scenarios that were <br />simulated included the following: <br /> Scenario 1 – Operation of new production wells at Del Prado Park, Tennis Park, and Hansen Park; <br /> Scenario 2 – Operation of new production wells at Tennis Park and Hansen Park; <br /> Scenario 3 – Operation of new production wells at Tennis Park and Del Prado Park. <br /> <br />Each of the three scenarios included development of separate monthly pumping amounts from each well <br />for Average/Wet Years and Drought Years. It was assumed that Average/Wet Years had a target total <br />production from the new wells of 6,500 AFY, whereas the Drought Year target total production was set at <br />9,000 AFY. Due to desired monthly pumping volumes and estimated pumping capacities, the target annual <br />volumes were not always able to be achieved and actual simulated pumping volumes for each scenario