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WASTE DISCHARGE REQUIREMENTS -6- FORWARD INCORPORATED WASTE MANAGEMENT FACILITY CLASS II LANDFILLS CLASS III LANDFILLS CLASS II SURFACE IMPOUNDMENT CLASS II LAND TREATMENT UNIT CLOSURE OF CLASS I LANDFILL SAN JOAQUIN COUNTY 25. Findings 15 through 24 indicate the water quality will be adequately protected during the closure and post -closure maintenance period. Therefore, the Board finds that the Discharger has satisfied the requirements of Section 2510(b) and approves the proposed engineered alternative to Section 2531(b)(1) for the in-place closure of WMU A. 26. Land within 1,000 feet of the site is used for agriculture. 27. The Forward Landfill is underlain by the Victor Formation. This is a heterogeneous formation composed of fan and flood plain deposits derived from Sierra granitics, metamorphics, and volcanics. Geologic materials immediately under the WMUs are lenticular clay, silt, sand, and minor amounts of gravel. Some of the lenses of clay, silt, and sand appear to be laterally continuous between monitoring wells over a distance of up to 1,800 feet. Others are discontinuous across the site. The lenses range from a few inches to approximately 20 feet in thickness. Based on geological cross-sections submitted with the Report of Waste Discharge, over 50 percent of the material within 60 Feet of the ground surface is coarse grained soil (Bureau of Reclamation, Unified Soil Classification). 28. The shallow ground water beneath the site is contained in the Victor Formation and recent alluvium. Generally, these sediments have moderate permeabilities with locally high permeabilities in the sandy and gravelly lenses. Ground water in the Victor Formation is unconfined and flows in a north -northeasterly direction beneath the site. The ground water table is 30-40 Feet below the bottom of the WMUs. The quality of this water is suitable for domestic or agricultural use. 29. The beneficial uses of ground water are municipal, domestic, agricultural, and industrial supply. 30. The site receives an average of 13.3 inches of precipitation per year as measured at the Stockton Airport between the years 1949 and 1980. The mean evaporation for this site is 78.4 inches per year as measured at Oakdale Woodard Reservoir between the years 1919 and 1968. Based on these data, average annual net evaporation at the site is 65.1 inches. 31. The 1,000 -year, 24-hour precipitation event for the site is 4.79 inches.