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 17 Soil cuttings, development water, and other investigation-derived waste generated during the boring advancement and/or well completion activities will be stored at the site in properly labeled California Department of Transportation approved containers. Soil cuttings will be transferred and disposed of in Forward Landfill. Development water will be allowed to settle before being transferred to the leachate collection pond at Forward Landfill, and the remaining solids will be disposed of as solid waste. 5.5.2 Extraction Well Design The proposed extraction well CDCR-EW-5 location is shown on Figure 7, and the well design details are presented in Table 17 and in Appendix I. The design for the extraction well will consist of a 6-inch, schedule 80 PVC riser and stainless-steel wire wrap screen, with a 20 to 30-foot length of screen, a slot size to be determined by sieve sample analysis, and a 5-foot blank sump. The well screen will be positioned in the intermediate WBZ will target the most permeable materials. The actual depth and well design will depend on the materials encountered. Centralizers will be placed at the top and bottom of the screen and close to the surface. The screen interval will be backfilled with silica sand to match the respective screen slot size so that a minimum of 5 feet of sand extends above the screen. The well will be periodically surged during placement of the filter pack to consolidate the sand. The extraction well annulus above the sand interval will be backfilled with a minimum of 5 feet of hydrated bentonite chips/pellets. Depth soundings will be utilized to evaluate the thickness and uniformity of the sand pack and bentonite seal to help ensure that no bridging occurs. The remaining annulus will be filled to the ground with a neat Portland cement grout and pumped into place using positive displacement tremie techniques. The well screen dimension, material, and slot size may change based on geologic observations. The extraction wellhead will be completed as required to enable pump installation and conveyance line installation to the GWET system and will include a concrete apron. 5.5.3 Well Development The extraction well CDCR-EW-5 will be developed no sooner than 48 hours after installation to allow adequate time for the well seal to cure. The well will be developed by airlift, surging, bailing and/or over-pumping to remove sediment introduced during drilling and/or well construction. During well development, the volume of any mud dispersant solutions or fresh water added (if necessary), water removed, and field parameters will be measured, including pH, electrical conductivity, turbidity, oxidation - reduction potential, dissolved oxygen, and temperature. Development will continue until the turbidity is reduced to less than 5 NTUs and/or when field parameters have stabilized (less than 10% variation in readings).