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 9 4.2.5 Monitoring Well Survey The groundwater monitoring and extraction wells were surveyed to the North American Vertical Datum of 1988 (vertical) and North American Datum of 1983 (horizontal) datum , and the survey data report is provided in Appendix E. A qualified, state-licensed land surveying firm, Ruggeri-Jensen-Azar, of Gilroy, California, performed the surveying on August 29, 2024. Prior to the wellhead survey, permanent markings were applied to the top of the well casing to provide reference points for the surveyors. The surveyed vertical elevation and horizontal coordinate data for the groundwater monitoring wells conforms to the reporting requirements of the California State Water Resources Control Board (2001) GeoTracker™ Survey_XYZ Guidelines & Restrictions and will be uploaded to the GeoTracker ™ database as part of the RWQCB reporting process. 4.2.1 Deviations from the Work Plan The following were deviations from the Work Plan (Arcadis 2023a): • The position of extraction well CDCR-EW-3 was relocated approximately 300 feet west of the proposed location. The well was relocated because soil samples collected from the proposed location only indicated a combined thickness of approximately 1.5 feet of permeable materials (i.e., sand and gravels) in the shallow and intermediate WBZs. The revised position was indicated by prior investigation activities (Arcadis 2023b) to contain a combined thickness of approximately 35 feet of permeable materials. • Monitoring wells AMW-61S and AMW-61M were added, and these wells were located adjacent to extraction well CDCR-EW-3. This well pair was required to provide aquifer monitoring in close proximity to extraction well CDCR-EW-3 for hydraulic testing. Monitoring wells AMW-60S and AMW-60M were installed at the original proposed location for extraction well CDCR-EW-3 and will be used ongoing for the CDCR plume delineation and control understanding. 4.2.2 Investigation-Derived Waste Soil cuttings and other investigation-derived waste generated during the boring advancement and well completion was stored in a stockpile in an approved location within the Forward Landfill property boundary. Soil cuttings were disposed of in the Forward Landfill. During each hydraulic assessment event and well development, wastewater was stored in a 21,000-gallon frac tank before being allowed to settle and was later transferred to the Forward Landfill leachate pond.