COMPLIANCE INFO_JTD APPENDIX A -L 2024

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North County Recycling Center & Sanitary Landfill Public Works/Solid Waste First Semiannual 2024 Groundwater Monitoring 11 ©2024 COUNTY of San Joaquin. All Rights Reserved. Second Quarter 2024 During Second Quarter 2024, groundwater elevations ranged from -73.47 feet MSL (G-12) to -49.63 feet MSL (G-14). The average groundwater elevation for wells G-7 through G-13 was of -66.03 feet MSL. During Second Quarter 2024, groundwater flow was generally to the west. Well G-12 had a historically low groundwater elevation (since installation in 2022) which may have been caused by nearby agricultural pumping. Groundwater flow toward the northwest had calculated gradients ranging from 0.0001 ft/ft (between wells G-10 and G-7) to 0.005 ft/ft (between wells G-7 and G-12). Groundwater flow to the southwest had a calculated gradient of 0.001 ft/ft between wells G-10 and G-9. Based on the calculated gradients at the site, the groundwater velocity ranged from approximately 3.4 ft/year to 168 ft/year (Appendix F). STANDARD OBSERVATIONS Site inspections were performed monthly during this semiannual period (Appendix H). No observations of any compliance issues were recorded during this reporting period. An electronic signature on the form certifies that all observations were performed and are accurate. Figure 2 depicts the Area of Fill during this semiannual period. RUN-OFF/RUN-ON FACILITIES The NCRC&SL utilizes several facilities to control run-on and run-off. A perimeter berm around the waste management unit prevents any run-on. This perimeter berm, along with a series of ditches, also controls all surface run-off during storm events, and directs surface run-off from the landfill to a retention basin on the east side of the site (Figure 3). The primary path for water entering the site is from a tributary of South Paddy Creek east of the site. Water entering from this source is diverted into the wetlands north of the site (Figure 3). LEACHATE COLLECTION AND RECOVERY SYSTEM Leachate is collected in the Leachate Collection and Recovery Systems (LCRSs) of the four landfill Areas. This leachate is returned to the refuse in accordance with the WDRs for this site. Landfill gas condensate is pumped into the LCRS of Area 4, and is handled as leachate also in accordance with the WDRs. The semi-arid climate of the North County Landfill and the waste shed from which the refuse is collected provides dry refuse in which the leachate can be absorbed. Leachate quantities do not typically indicate significant intrusion of water, or difficulty in meeting regulatory limits. Normal operation of the leachate system at the North County Landfill provides redundancy in absorption. Leachate may be pumped to the deep infusion points, to a leachate storage tank, or to the active landfill face if the active face is over Area 3, 4 , 5, or other future lined Areas.