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WELL INSTALLATION AND INTERIM REMEDIAL ACTION REPORT <br />www.arcadis.com <br />FINAL_Forward CHCF (CDCR) Well Installation Report_10182024 <br /> <br />7 <br />approximately 5 feet above the top of the shallower screen interval. A 5-foot-thick hydrated bentonite pellet seal <br />was placed above the sand pack. The remainder of the annular space was filled with neat cement grout. There <br />was no steel monument or concrete pad constructed for the extraction well, which will be constructed later when <br />connected to the planned GWET system. Three bollards were installed surrounding the well riser stick-up. <br />4.2.3 Extraction and Monitoring Well Development <br />This section describes the well development activities completed in May 2024 at the CHCF and in July/August <br />2024 at the NCYCC <br /> May 2024 Extraction and Monitoring Well Development (CHCF) <br />Development of monitoring wells AMW-60S and AMW-60M and extraction well CDCR-EW-4 was performed on <br />May 21 and 22, 2024, a minimum of 48 hours after well installation to allow adequate time for the well seals to cure. <br />The wells were surged and bailed using a surge block and bailer. A well development rig operated by ABC Drilling <br />was used to dislodge fine-grained sediment from the filter pack and enhance the hydraulic communication between <br />the respective well screen and surrounding water-bearing formation. <br />The monitoring wells and extraction well were developed through multiple rounds of bailing and surging, followed <br />by purging with submersible pump until stability of water quality parameters (including pH, conductivity, and turbidity <br />[less than 10% variation in readings]) was achieved. This process was repeated until the turbidity in the water <br />removed was less than 5 nephelometric turbidity units (NTUs). Depth-to-water measurements and further <br />development details for wells are presented in Appendix D-1. <br /> July/August 2024 Extraction and Monitoring Well Development (NCYCC) <br />Development of monitoring wells AMW-61S and AMW-61M and extraction well CDCR-EW-3 was performed on <br />July 29 through August 7, 2024, a minimum of 48 hours after well installation to allow adequate time for the well <br />seals to cure. The wells were surged and bailed using a surge block and bailer. A well development rig operated by <br />ABC Drilling was used to dislodge fine-grained sediment from the filter pack and enhance the hydraulic <br />communication between the respective well screen and surrounding water-bearing formation. <br />The monitoring wells were developed through multiple rounds of bailing and surging, followed by purging with <br />submersible pump until stability of water quality parameters (including pH, conductivity, and turbidity [less than 10% <br />variation in readings]) was achieved. This process was repeated until the turbidity in the water removed was less <br />than 5 NTUs. <br />The extraction well was developed through multiple rounds of bailing and surging, and air lifting, followed by <br />purging with a submersible pump until stability of water quality parameters (including pH, conductivity, and turbidity <br />[less than 10% variation in readings]) was achieved. To improve the sustained pump rate of extraction well CDCR- <br />EW-3, development continued using the airlift method, which involves using compressed air. Airlifting was <br />conducted using a 5-foot-long airlift pump to develop each section of the well screen until the turbidity in the water <br />removed was less than 100 NTUs at each 5-foot section of the well screen. Additional development by surge and <br />bailing and pumping was repeated until the turbidity in the water removed was less than 5 NTUs. Depth-to-water <br />measurements and further development details for wells are presented in Appendix D-1.