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Mr. Brenden Kenny Central Valley Regional Water Quality Control Board March 7, 2022 bentonite seal, to assure that no bridging occurs. The remaining annulus will be filled to the ground with a neat Portland cement grout, pumped into place using positive displacement tremie techniques. The well screen dimension, material, and slot size may be subject to change based on geologic observations and site conditions. The extraction wellhead will be completed as required to enable pump installation and conveyance lines installation to the treatment system, including a 4-foot-wide concrete apron. Piezometer Design The proposed groundwater piezometers are located on Figure 1, with design presented in Table 1 and in Attachment 1. The design will consist of a 2-inch schedule 40 PVC pipe, with depth and screen interval comparable to the extraction well and lithology encountered. The piezometers will be completed with 0.01 inch slot size screen, matching filter pack, anticipated as#2/12 silica sand, ensuring that a minimum of 3 feet of sand extends above the screen. Additional installation and well development details are provided in the Work Plan (Arcadis 2019). Extraction Well Hydraulic Step Test A hydraulic step-drawdown test will be performed on the installed groundwater extraction well. The data obtained from this test will be used to establish the well yield, specific capacity, and pumping rate for the constant rate test and to estimate the hydraulic characteristics of the surrounding formation. Prior to performing the step-drawdown test, the development drawdown trends will be reviewed to assess achievable pumping rates and confirm the size of the test pump. The step-drawdown test will be performed by pumping the extraction well at a set of sequentially increasing pumping rates and measuring the change in water level in the pumping well and adjacent piezometers to be installed as part of this scope. The water levels will be monitored immediately prior to and during testing using pressure transducers with integral data logging capabilities, as well as manual water-level measurements. Water- level monitoring will continue through the well recovery period. Manual water-level measurements will be collected using an electronic water-level indicator with gradations to the nearest 0.01 foot, before testing to determine static water levels, as well as during the tests, to confirm the transducer data, after water levels stabilize, and then once before completing the step-drawdown test. During step-drawdown testing, the flow rate will be periodically measured using an inline flow meter and adjusted to maintain constant steps. For each pumping step, the flow rate will be maintained for at least 30 minutes, or until drawdown has stabilized (less than 10% change in total drawdown over 15 minutes). At least three pumping rates will be assessed, with the actual pumping rates adjusted based on field conditions. Produced water will be pumped into a temporary storage container, likely a baker tank, to be later transported to Forward Landfill for treatment and disposal. After completion of the step-drawdown test, water-level data will be downloaded from the data loggers for analysis. The analysis will include preliminary estimates of well yield and the hydraulic properties of the groundwater in the water bearing zone. The analysis will also be used to select the appropriate pumping rate for the longer-term constant-rate test. Extraction Well Constant Rate Test Upon evaluation of the data generated during the step-drawdown test and after water elevations have recovered to baseline conditions, a constant-rate pumping test will be performed at the extraction well. The pumping rate www.arcadis.com 5/9