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0.0021 foot per foot. The calculated average linear groundwater flow velocity in the fourth quarter was 58.55 feet per year based on a hydraulic gradient of 0.0017 foot per foot (Appendix G). The hydrographs indicate a general decline of water levels from a high water level mark in 2000. This appears to be a result of a general regional change water level elevation. STANDARD OBSERVATIONS Regular site inspections were performed during the second semester of 2007. Monthly standard observations have been summarized(Appendix H). The electronic signatures on the forms certify that all observations were performed and are accurate. The intense,but short-duration storms of late December 2007 did not significantly impact the surface of the landfill. 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 a point of compliance, as stated in the WDRs. 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 an18-inch diameter HDPE pipe ■ A 2-foot deep secondary extraction trench beneath the primary composite liner, with 12-inch HDPE riser pipe ■ A pumping system that allows recording of leachate flows and volumes ■ A 10,000 gallon leachate storage tank Foothill Sanitary Landfill 10 Department of Public Works/Solid Waste 2nd Semester and Annual 2007 Groundwater Monitoring County of San Joaquin—January 31,2008