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Zone 7 Water Agency – Hansen Park Test Well Summary <br />and Production Well Design Recommendations <br />8 Zone 7 Water Agency <br />December 2025 <br />Table 10. Summary of Well Pumping Capacity Estimates <br />Well ID <br />Proposed <br />Top of <br />Screen (ft <br />bgs) <br />24-Hr Q/s <br />(gpm/ft) <br />High <br />Available <br />DD (ft) <br />Low <br />Available <br />DD (ft) <br />Assumed <br />Well <br />Efficiency <br />(%) <br />High <br />Pumping <br />Capacity <br />(gpm) <br />Low <br />Pumping <br />Capacity <br />(gpm) <br />Hansen <br />Park 298 30.5 273.5 223 50 4,200 3,400 <br />The well capacity estimates provided in Appendix C, 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 />3.PRODUCTION WELL DESIGN RECOMMENDATIONS <br />Based on our investigation of the Hansen Park site, the testing of the Hansen Test Well, and our well yield <br />and drawdown analysis, LSCE believes that a well constructed at the Hansen Park site could yield between <br />3,400 to 4,200 gpm of water that would meet all current Title 22 Drinking Water Standards without <br />treatment. Utilizing the information gathered as part of the site investigation, well testing, and analysis, <br />LSCE has prepared the following design recommendations for a community supply well to be constructed <br />at Hansen Park. <br />Our proposed well design meets the requirements of the Department of Water Resources Water Well <br />Standards, Bulletin 74-81, 74-90; State Water Resources Control Board, Division of Drinking Water (DDW), <br />and accepted water well design standards. Figure 6 depicts the proposed well design. The well is designed <br />to accommodate submersible pumping equipment that could pump up to 4,200 gpm. Collapse pressures <br />for each casing type and thickness were calculated to ensure each can resist the hydrostatic pressures <br />developed during sanitary and annular seal placement. Each of the well design elements is discussed <br />below. <br />Conductor Casing / Sanitary Seal – The conductor casing will stabilize the upper portions of the borehole <br />during drilling and well construction, while ensuring that requirements for sanitary seal are met. The <br />conductor casing shall be installed in a 60-inch diameter borehole and cemented in place to a depth of 95 <br />feet bgs. At a depth of 95 feet, the conductor will terminate in a clay layer. The conductor casing shall be <br />fabricated of a 48-inch O.D. by 1/2-inch wall ASTM A-139 Grade B steel. <br />Production Borehole – The production borehole shall be drilled using the reverse circulation drilling <br />method. The final borehole diameter shall be 40 inches to a depth of 775 feet bgs.