Evaluation of Groundwater Supply Alternatives Within Bernal Subbasin

Zone 7 Water Agency – Tennis Park Test Well Summary and Production Well Design Recommendations 4 Zone 7 Water Agency December 2025 pumping duration, projected pumping drawdown, and projected specific capacity of the test are included below in Table 3. The long-term constant rate test hydrograph is depicted in Figure 5. Table 3. Long-Term Constant Rate Test Results Duration (min) Average Discharge Rate (gpm) Projected 24-Hour Drawdown (ft) Projected 24-Hour Specific Capacity (gpm/ft) 480 549 26.5 56 2.3. Water Quality Water quality samples were collected by LSCE personnel from a dedicated sample tap on the well discharge assembly on April 8, 2025, for drinking water constituent analysis and for other constituents of interest. Water samples were collected and handled according to the Testing, Sampling, and Analysis Plan (Appendix A) prepared for the project and standard industry practice. All collected samples were submitted for analysis at the same time. Due to a laboratory error, analysis for twenty-seven constituents was not performed. The results of the water quality analysis show that all constituents analyzed were below their respective maximum contaminant levels (MCL). Appendix B summarizes the results of analysis results. The constituents that were not analyzed were either below their respective MCL’s or were not detected. While meeting drinking water quality standards, hardness, nitrite, and total dissolved solids values exceed Zone 7/City of Pleasanton’s water quality targets. The exceedances are summarized in Table 4. Table 4. Water Quality Targets and Exceedances Parameter Target Result Hardness 150 mg/l 440 Nitrite 0.02 mg/l 0.87 Total Dissolved Solids 500 mg/l 820 2.4. Zone Sampling Depth-discrete water samples were collected from above each screened interval within the well to characterize zonal water quality. Groundwater samples were collected on April 9, 2025, under pumping conditions. Starting with Zone #1, Pacific Surveys installed a sampling tool into the well to the specified zone to collect a sample for analysis. Samples were analyzed for general mineral, general physical, inorganic, and PFOS/PFAS constituents. Water samples were collected and handled according to the Testing, Sampling, and Analysis Plan prepared for the project. A summary table of zonal water quality analysis results are in in Appendix B. Samples were collected at the depths shown in Table 5.