ARCHIVED REPORTS_2004 - Laserfiche WebLink

Home Browse Search

qp 6.7 GAS MANAGEMENT PLAN San Joaquin County prepared a Methane Monitoring Program (August 29, 2003) and currently monitors landfill gas at the landfill in accordance with that monitoring program. As discussed in Section 5.2, the County concluded that the cause of impact at groundwater well G-4 was landfill gas, and that sporadic detections at G-4 were likely to occur unless corrective action was taken. The County submitted an Engineering Feasibility Study to the RWQCB on August 12, 2004. The corrective action methods evaluated included: landfill gas collection, soil gas collection with treatment, and soil gas collection without treatment. The evaluation indicated that soil gas collection with treatment was the most favorable method of corrective action. The County is currently evaluating another remedial approach where pressure is applied under the liner, rather than vacuum. Once a remedial approach is selected, the approach will be implemented at the landfill. This implementation will be followed by development of a landfill gas management plan for the facility. 6.8 ENVIRONMENTAL MONITORING Water quality is monitored consistent with WDR Order No. R5-2002-0219 (Appendix A). The groundwater network consists of five groundwater monitoring wells, two surface water monitoring points, five unsaturated zone points, three leachate sumps, eight soil gas wells, and one soil gas trench(Plate 5). , 6.9 FINAL GRADING PLAN The proposed landfill configuration is shown on the final grading plan for the site (Plate 13). The landfill configuration is controlled by the existing refuse fill, surrounding topography, drainage, stability requirements, aesthetics, visibility, and end-use considerations. Final grades will be constructed with slopes no steeper than 3:1 (horizontal: vertical) to reduce erosion, and no flatter than 3 percent to provide sufficient slope for storm water runoff after refuse consolidationp and settlement. The 3:1 slopes will be constructed with 15-foot minimum width benches to limit landfill slope lengths and to provide for surface runoff without promoting North County RC&SL Page 30 of 48 Public Works/Solid Waste JTD County of San Joaquin—November 30,2004