Evaluation of Groundwater Supply Alternatives Within Bernal Subbasin

Zone 7 Water Agency – Tennis Park Test Well Summary and Production Well Design Recommendations 3 Zone 7 Water Agency December 2025 February 10, 2025. Test well construction was completed on February 21, 2025. A copy of the Well Completion Report is attached (Appendix A). 2.2. Well Development and Testing Initial development of the well was performed by open-ended airlifting from the bottom of the casing assembly, followed by swab/airlift development by Nor-Cal. Final developmental pumping was performed with a submersible pump by North State. Starting on February 25, 2025, the drill string was installed to the bottom of the casing, and the well was airlifted open-ended. Between February 25 and March 7, 2025, a swab isolation tool was used to swab/airlift each well screen. The screened sections were swabbed/airlifted from the top screen section to the bottom screen section, and then from the bottom screen section to the top screen section over multiple passes. All fluids generated during airlift operations were contained and disposed of offsite by Nor-Cal. After airlift operations were completed, LSCE collected water samples from the well for analysis of volatile organic compounds (VOCs), fuel additives, semi-volatile organic compounds (VOC’s), polycyclic aromatic hydrocarbons (PAH’s), and metals listed in NPDES Permit No. CAG912002. A summary table of analytes and analysis results is included Appendix A. Only after the results of the water testing and discharge plan (Appendix A) were accepted by the City of Pleasanton, was water discharged to the City’s storm water system. Storm drain discharge monitoring field notes are included in Appendix A. North State installed a temporary submersible pump in the well to perform pump and surge development of the well and to conduct well testing. Between April 2, 2025, and April 4, 2025, the well was developed at rates between 200 and 650 gallons per minute (gpm). Step Test Step testing was performed on April 8, 2025, and consisted of three (3) steps. The static water level in the well measured prior to testing was 16.55 feet bgs. The discharge rate, pumping duration, projected pumping water drawdown, and projected specific capacity of the test are included below in Table 2. The step test hydrograph is depicted in Figure 4. Table 2. Step Testing Results Duration (min) Average Discharge Rate (gpm) Projected 24-Hour Drawdown (ft) Projected 24-Hour Specific Capacity (gpm/ft) 120 329 21.1 72.3 120 493 23.6 66.2 240 613 27.8 53.5 Long-Term Constant Rate Test An 8-hour constant rate pumping test was performed on April 9, 2025, to determine well and aquifer characteristics. The static water level measured prior to testing was 16.70 feet bgs. The discharge rate,