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Groundwater Well Installation Work Plan Sharpe Army Depot Lathrop, California 11. Check that the power supply or generator for the submersible pump is ready, piping is in place, the discharge rate has been determined and set, and the data logging equipment is ready.The initial discharge rate for the step-drawdown test is 40 gpm for all proposed extraction wells.The discharge rate for the constant-rate test will be determined based on the results of the step- drawdown test. 12. Turn on data loggers for all transducers before starting the pump in the test well. Record the test start time. 13. Begin to measure water levels periodically using a manually operated water level meter to check the transducer readings' accuracy and provide backup data if the data logger fails. Check water levels more frequently at the beginning of the test when levels change rapidly(i.e., every minute for the first 10 minutes and every 2 minutes for the next 10 minutes). 14. Begin to check the pumping discharge rate periodically using the flow meter to check that the well is being pumped at the appropriate discharge rate. Also, check the flow rate by comparing it to the totalizer flow meter reading. Record the flow rate on the aquifer constant-rate test field data sheet(Appendix B). 15. After pumping the well for the specified test duration, set the data logger to begin recording recovery and shut off the pump. 16. After monitoring recovery until the water level in the test well is within 10 percent of its pre- pumping water level, remove the pump and transducers from the wells. 17. Transfer the test data from the data logger to an appropriate data storage device (such as a personal computer or tablet) using the downloading procedures from the data logger. Pumping test data will be analyzed using AQTESOLV"', an industry-standard software package used to design and interpret aquifer tests. Analyses may include one or more of the following: • Neuman type curves for delayed yield analysis (Neuman, 1975) • Leaky Aquifer Method (Hantush, 1956), Distance-Drawdown (Jacob, 1963), or Residual Drawdown Method (Jacob, 1950)for transmissivities and hydraulic conductivities • Leaky Aquifer Method (Hantush, 1956) method for storativity values • Other methods, as applicable, based on site conditions and test results Data from the constant-rate tests will be used to calculate transmissivity and storativity. 3.2.4 Surface Completion Surface completions will be above-ground and flush-mounted.Tags will be attached to every well lid that lists the well depth, screen interval, location coordinates, surface elevation, alphanumeric identification, and monitoring zone designation. Extraction Wells For all extraction wells,a 16-inch diameter locking steel casing set into a concrete pad (approximately 8 ft by 4 ft by 6-inch) will be installed around each well. The top of the steel casing will be set approximately 3 ft above the ground surface. The concrete pad will be sloped from the edge of the steel casing to the edge of the pad and smoothed with a trowel to facilitate the flow of surface water away from the well. Ahtna Environmental,Inc. 15