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Central Valley Regional Water Quality Control Board <br /> June 30, 2025 <br /> Page 4 <br /> WELL DEVELOPMENT AND SURVEY METHODS <br /> A minimum of 48 hours after installation, each well will be developed using surge-and-purge methods. <br /> The screen interval of the well will first be surged with a surge block,then a bailer will be used to <br /> remove any accumulated sediment at the bottom of the well after surging.The well will then be purged <br /> until groundwater field parameters (turbidity, pH, temperature, dissolved oxygen, oxidation-reduction <br /> potential, and specific conductance) stabilize.The pumping rate and drawdown will be recorded during <br /> development to estimate the specific capacity. <br /> Haley&Aldrich will contract with a California-licensed surveying company to survey the horizontal <br /> location and vertical elevation of the top of each well casing, as well as ground surface elevations <br /> adjacent to the wells. The horizontal location will be surveyed relative to the North American Datum of <br /> 1983 and the elevation will be surveyed relative to the North American Vertical Datum of 1988. <br /> DECONTAMINATION AND WASTE MANAGEMENT <br /> All reused down-hole equipment (such as drill casing)will be decontaminated using a pressure washer <br /> or steam cleaner in between individual well locations. Soil cuttings and decontamination/development <br /> water will be containerized separately pending profiling and disposal at an appropriate facility. <br /> INSTRUMENT INSTALLATION AND WELL SAMPLING <br /> Following installation activities, pressure transducers will be installed in piezometers PZ-01 and PZ-02 to <br /> assess the hydraulic head in the aquifer during operation of the NATS injection wells. A passive diffusion <br /> bag will be deployed in newly installed monitoring well M-57C1 and sampled during the next quarterly <br /> sampling event. Per the Revised Monitoring and Reporting Order No. R5-2014-0815-03, M-57C1 will be <br /> sampled quarterly following the sampling and analysis procedures described in the Revised Quality <br /> Assurance Project Plan (Haley&Aldrich, 2022). <br /> RICH <br />