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i GROUNDWATER DIRECTION AND FLOW RATE Groundwater elevations were measured in monitoring wells MW-1, MW-2R, and MW-3 during the third and fourth quarters. Groundwater was determined to flow towards the southwest (Figures 3 and 4). The groundwater gradient is 0.0016 foot per foot, calculated from the drop in t water elevation from 52 feet to 50 feet MSL over a distance of 1250 feet. These calculations can be found in Appendix G. STANDARD OBSERVATIONS Regular site inspections were performed during the second semester of 2006. Monthly standard observations have been summarized (Appendix H). The electronic signatures on the forms certify that all observations were performed and are accurate. RUN-OFF/RUN-ON FACILITIES The Foothill Sanitary Landfill utilizes several methods to control run-on and run-off. The natural topography of the area controls any run-on into the site. Also, the working area is a significant distance from the property boundary, so run-on from surrounding properties is minimal. To control run-off, a perimeter ditch along the north, west and east ends of the unit directs all storm water run-off into a sedimentation basin on the east side of the site. The rest of the run-off from the unit gathers into a sedimentation basin at the southeast corner of Module 1. There were no breeches to any of the run-on/run-off facilities during this monitoring period. OTHER ANALYSIS Groundwater samples were collected from landfill supply well LW-1 and analyzed for all monitoring and field parameters. The well is not considered a point of compliance, as stated in the WDRs. Results are included in Table 2 and Appendix E. LEACHATE COLLECTION AND RECOVERY SYSTEM - PROCEDURES & MAINTENANCE Facilities The leachate collection and recovery system (LCRS) for Module 1 was designed in accordance with Title 27, Section 20340(g). This system consists of: ■ East/west oriented collection troughs running the entire length of Module 1 ■ A 4-foot deep sump at the southeast corner of the Module ■ A leachate removal pump installed in an 18-inch diameter HDPE pipe ■ A 2-foot deep secondary extraction trench beneath the primary composite liner, with 12-inch HDPE riser pipe Foothill Sanitary Landfill 8 Department of Public Works/Solid Waste 2m Semester Groundwater Monitoring County of San Joaquin—January 31,2007