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i i. Leachate quantities do not 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, to the active landfill face if the active face is over Area 3, 4, or other future lined Areas. Facilities The leachate facilities for each Area include: ■ Sump with dedicated leachate pump. ■ Volumetric flow meter for the sump pump, indicating total gallons pumped(the meter for Area 4 also indicates instantaneous flow rate). ■ A leachate storage tanks. These tanks are normally not in use but are available if leachate cannot be returned to the refuse directly from the sump. o Areas 1 and 3 sumps share one tank(3,000 gallons) o Area 4 is provided with a separate tank(12,000 gallons). ■ Float switches within each leachate tank activate alarms based on high or low level conditions. o Under high-level conditions,the leachate sump pump are deactivated. This prevents overflow of the tanks. o Under low-level conditions,pumps that can remove leachate from the tanks are deactivated,preventing the operation of these pumps with insufficient fluid. ■ Transfer pumps at each leachate tank which can deliver leachate into a water truck if needed. ■ Return pump at Area 4 leachate tank to deliver leachate to a location other than a water truck, if needed. Although not yet needed, this pump would be used to deliver leachate to a Area with a Subtitle D-approved liner. Semi-permanent points of return of leachate to the refuse include three Deep Infusion Points ("dry" wells), all installed over Lined Area 3. The highest elevation of the base of Area 3 in this area is approximately 96 NGVD. The bottom of these Deep Infusion Points (DIPs) are approximately at elevation 140 ft NGVD. Approximately 50 feet of refuse in multiple lifts exists between the point of infusion and the base of the landfill. Construction and alteration of the DIPs was reported in detail in the First Semester 2005 Groundwater and Surface Water Monitoring Report. Leachate was not returned to DIPs in this monitoring period. Additional infusion areas have been constructed in Area 4 as needed to accept leachate. Normal Operation Leachate drains by gravity to the Area sumps from which it is pumped directly to the landfill refuse per the WDRs. The sump pump operates automatically, based on leachate levels within the sump. Operation of any Area sump pumps is conditional upon sufficient water in the sump (indicated by the level sensor on the pump)and available capacity in the associated leachate tank(indicated by the float switch in the tank). Control points for the pumps are: North County RC&SL Public Works/Solid Waste 1"Semiannual 2014 Groundwater Monitoring 9 County of San Joaquin—July 31,2014