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Leachate production rate is greater in the late winter and spring, compared to summer and autumn,because little or no rain falls on the site from April to November of each year. The secondary leachate sump is monitored monthly for the removal of LFG condensateLandfill Gas Condensate Removal from Module 1 Secondary Sump The pump permanently installed in the secondary sump under Module 1 operates once three days per week, pumping liquid, if any, from the secondary sump into the primary sump. Once started,the pump operates until pump protection circuits stop pumping due to insufficient liquid. A meter is provided to monitor the liquid removed. The depth of liquid in the secondary sump is also monitored monthly using by a bubbler tube installed into the sump. Measurements indicate that the pump is maintaining the liquid level at the minimum level that allows the pump to remove liquid. HISTORICAL TIME SERIES PLOTS Constituents not detected are plotted at a value of half their respective detection limits in the Historical Time Series Plots (Appendix F). Outliers were included in the plots as directed by RWQCB staff. PROGRESS OF EVAPOTRANSPIRATION COVER The purpose of the evapotranspiration cover is to capture rain water during the wet months, allowing the vegetation growing on that cover to remove the water from the soil during the dry months,restoring the storage capacity of the soil for the next rainy season. Providing storage for rainwater each year prevents the percolation of water into the refuse. The intention of this closure method is to minimize water percolating into the refuse at least as effectively as the prescriptive barrier layer(one foot thick with permeability of 10"6 cm/sec or less). A key component of this method is the vegetation on the cover. Perennial plants, such as purple needle grass and California Brome, send roots deep within the soil to gather moisture,providing storage capacity during the rainy season. In contrast, annual species, such as rye grass,may produce a thick cover during their growing season, but produce shallow roots which cannot remove moisture from deep within the cover layer. The ET cover was established in December 2008 when the soil of much of the top deck area was amended, fertilized and reseeded. The cover vegetation continues to flourish. Results of monitoring in the 20010-2011 rain year indicate that the ET cover is successful, that the measured percolation in the test area is gpproximately one-half of that calculated for an intact prescriptive cover(report previously submitted). The surfaces of the landfill, including the ET cover area, are grazed annually to facilitate inspection by the LEA. Foothill Sanitary Landfill 14 Department of Public Works/Solid Waste 1 n Semester 2012 Groundwater Monitoring County of San Joaquin—July 17,2012