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

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Forward Inc. - 2 - 24 March 2022 and AMW-22s were VOCs exceed 25 µg/l. 2). Perform hydraulic testing (step- drawdown test, constant rate pumping test) to assess aquifer characteristics.3). Conduct a site investigation of the CDCR property using Cone Penetrometer Testing (CPT) Borings to sample groundwater and soil vapor to assess if additional sources of VOCs, primarily Carbon Tetrachloride and Chloroform are present on-site., and 4). Evaluate the required interim remedial action design based on the results of the site investigation. Staff Comments: The installation of extraction well(s) is one component of the CAO. Forward Inc must also demonstrate compliance with the performance requirements of the CAO, which includes creating a measurable inward gradient from the wells along the edge of the plume as well as extracting from all zones affected by the release. The workplan omits some details regarding the extraction well installation, aquifer testing and the proposed site investigation of the CDCR property that should be considered prior to implementing the workplan. Therefore, Forward Inc, should review the comments below and evaluate if the proposed scope of work in the workplan should be expanded to address all requirements of the CAO. • The proposed installation and operation of a single groundwater extraction point may not be sufficient to comply with Item 3.c of the CAO that requires “…the extraction well(s) create an inward gradient of the groundwater table, measured from existing monitoring wells within the plume, in all zones affected by the release.” Additionally, because no extraction wells are proposed in the intermediate zone where VOCs are present, the Extraction Well Installation Summary Report and Site Investigation Report must include additional extraction well(s) to address the VOC impacted intermediate zone as required by the CAO. • In the 27 December 2018 response to the 2018 “Well Installation and Hydraulic testing at the Forward Landfill” work plan, the Regional Board requested additional analysis of the material recovered from the borehole of the to be installed extraction well. Again, this information should be collected during this field work for analysis. Because these will be extraction wells, the aquifer material should be sieved to verify the appropriateness of the well screen slot size and filter pack, as well as provide information necessary for designing and constructing additional extraction wells. • As was previously stated in the approved 2018 “Hydraulic Testing at the Forward Landfill” work plan, for at least 24 hours prior to the pump test, water levels in all pumping wells, groundwater monitoring wells and piezometers should be monitored to establish regional water level trends. • The workplan proposes to conduct a constant rate pumping test for up to 8 hours, and/or until water storage capacity has been reached. During the test the workplan proposes to monitor groundwater elevations in adjacent piezometers and groundwater monitoring wells AMW-22 and AMW-22s will be observed. The truncation of the pump test should not be limited to 8 hours or available