COMPLIANCE INFO_EW-5 INSTALL PERMIT PACKAGE 2/14/25

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WELL INSTALLATION AND INTERIM REMEDIAL ACTION REPORT www.arcadis.com FINAL_Forward CHCF (CDCR) Well Installation Report_10182024 8 4.2.4 Hydraulic Testing Hydraulic testing was conducted on extraction wells CDCR-EW-3 and CDCR-EW-4 to assess the extraction well production capacities and aquifer response to extraction, to establish aquifer hydraulic parameters, and to assess and calculate the groundwater capture zone of each extraction well. A step test was performed on extraction wells CDCR-EW-3 (August 8, 2024) and CDCR-EW-4 (May 22, 2024) after well development was completed. Before performing the step tests, the well development data and associated drawdown trends were reviewed to assess achievable pumping rates. The hydraulic test pump was specified to have a maximum pumping rate that was close to, or exceeded, the anticipated well capacity. The step tests were performed by pumping the extraction wells at a set of sequentially increased pumping rates. The water level in each pumping well was monitored immediately before testing, during testing, and through the recovery period manually and using a pressure transducer. The well header and pipework were configured for the flow gauge and totalizer to be placed in a straight section of pipework to avoid turbulent flow conditions and with flow restricted by an inline gate valve. The step test results for extraction wells CDCR-EW-3 and CDCR-EW-4 are presented in Tables 2 and 3, respectively, and the field data are presented in Appendix D-2. For each pumping step, the flow rate was maintained until drawdown had stabilized (less than 10% change in total drawdown over 15 minutes). The data obtained from these tests were used to establish the specific capacities of the extraction wells, determine the optimal pumping rates for the constant rate test, and enable the specifications for permanent pumps to be determined. Constant rate tests were conducted after recovery of the water level static conditions. A constant rate test was conducted on extraction well CDCR-EW-3 on August 9, 2024. Well construction details and the hydraulic test setup for the extraction well CDCR-EW-3 constant rate test are presented in Table 4, and the field data presented in Appendix D-3. A monitoring well network of 10 wells was used to assess changes in water levels to the shallow and intermediate hydraulic units during the hydraulic test. The monitoring wells were located between 11 and 1,535 feet away from the pumping well. Extraction well CDCR-EW-3 was pumped at a rate of 24.1 gallons per minute (gpm) for 8 hours, with water levels in the pumping and monitoring wells assessed before and during pumping and monitored overnight for groundwater recovery. Water levels were collected manually and by pressure transducers (Table 4). A constant rate test was conducted on extraction well CDCR -EW-4 on May 23, 2024. Well construction details and the hydraulic test setup for the extraction well CDCR-EW-4 constant rate test are presented in Table 5, and the field data are presented in Appendix D-3. A monitoring well network of six wells was used to assess changes in water level to the shallow and intermediate hydraulic units during the hydraulic test. The monitoring wells were located between 11 and 640 feet away from the pumping well. Extraction well CDCR-EW-4 was pumped at a rate of 16.5 gpm for 8 hours, with water levels in the pumping and monitoring wells assessed before and during pumping and overnight for recovery. Water levels were collected manually and by pressure transducer (Table 5). After completion of the pumping tests, the water level data were downloaded from the transducer data loggers for analysis. The aquifer transmissivity and hydraulic conductivity were estimated using AQTESOLV™ software applying the Theis step test solution for the step tests and Theis, Cooper-Jacob, and Hantush solutions for the constant rate tests (Thies 1935; Cooper 1946; Hantush 1960). The well capacity and aquifer parameters were then used to assess anticipated capture zones. Analysis and discussion of the results for the hydraulic tests, along with predicted well capture estimates, are presented in Section 5.