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Draft Environmental ImpactP Report Page III-18 Forward Inc. Landfill Expansion pipes. The LCRS collection header pipes slope at a minimum of one percent toward the sumps. The piping and drainage layer would be directly underlain by the composite lining system. A geotextile would be used under all pipes to protect the HDPE geomembrane liner from potential abrasion caused by the pipes. The drainage layer would be separated from the operations layer above by a nonwoven geotextile to prevent migration of fine-grained material into the LCRS. The LCRS designfor slopes greater than 15 percent would consist of a-geocompo`site drainage-net P _� (GDN)7GDN would-be used dile-to"construction and stability concerns associated with placement of granular materials on steep slopes. No collection pipes are required on the side slopes. Leachate collected in the LCRS would flow through the drainage layer to the pipes and subsequently into leachate collection sumps. Submersible pumps located in each sump would pump leachate from the LCRS to lined surface ponds,from which the leachate evaporates. Three leachate evaporation impoundments are permitted at the site,of which two are currently in use. WMU F North is located in the southwest region of the existing Forward Landfill,just north of the South Branch. It was constructed in 1999 and provides containment for leachate from the active portions of the southern WMUs. The leachate impoundment was sized based on actual leachate generation records from 1991 to 1997 and has a design capacity of approximately 3.5 million gallons. WMU F West is located in the northern portion of the site, directly west of WMU FU-03. It was constructed in 2003 and receives leachate from the northern waste management units. A third impoundment,WMU F South,has not yet been constructed as no waste has yet been landfilled south of the South Branch. If, during the service life of the landfill, the demand on the leachate impoundment exceeds capacity, Forward, Inc. would implement an alternative leachate management plan. Leachate in excess of the impoundment's capacity would either be pumped to temporary onsite tanks, trucked for off-site disposal at the City of Stockton Municipal Utility Department wastewater treatment plant located at 2500 North Navy Drive in Stockton, or trucked to another off-site licensed Treatment and Disposal Facility. Leachate stored in the temporary on-site tanks may be released back into the impoundment at a later date. Leachate Monitoring To monitor the LCRSs, Forward,Inc.conducts a leachate monitoring and sampling program in compliance with WDR Order No. R5-2003-0049. Quarterly and annual reports of the monitoring results are submitted to the DTSC,RWQCB, and the San- Joaquin_County,Public:Health Services Department;Environmental-Health-Division,.which is the Local Enforcement Agency(LEA). A leak detection system is also located under the sumps in the WMUs. The leak detection system currently consists of 14 suction cup lysimeters and pan lysimeters installed at the southern portion of the existing Forward Landfill. (A lysimeter is a device that measures percolation of water and removal of soluble constituents.) The lysimeters are sampled and tested in accordance with the site's WDRs. The northern portion of the site (former Austin Road Sanitary Landfill) has no leachate collection system and therefore no lysimeters. Groundwater Monitoring The groundwater-monitoring system at the existing Forward Landfill is designed to detect the presence of contaminants in groundwater by analyzing groundwater chemistry at point-of-compliance wells. The monitoring system consists of 36 groundwater-monitoring wells, which meet the requirements of the landfill's Detection Monitoring(DMP)for groundwater