COMPLIANCE INFO_1991-1997 - Laserfiche WebLink

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CITY OF • AUSTIN ROAD LANDFILL FACILIT CLASS III LANDFILL SAN JOAQUIN COUNTY The City of Stockton presently owns and operates a Class III landfill in Section 3. T1N, R7E, MDB&M, approximately six miles southeast of Stockton, on Austin Road. The site consists of 187 acres, of which 1.5 acres is for Newcastle right-of-way, 16.5 acres are for flood control easement, 124 acres are for landfilling, and 45 acres are used as a borrow area. The 187 -acre facility, Assessor's Parcels 201-060-01 and 05, was originally opened in 1954, temporarily closed from 1961 to 1963, closed to public use since 1964. and is now used by commercial collectors of Class III residential, commercial, and industrial solid waste Generated within the incorporated boundaries of the City. The site is currently accepting approximately 525,000 cubic yards (150,000 tons) per year. The city has accepted, on a one-time basis, approximately 20.000 cubic yards of digested sewage sludge from the City's wastewater treatment plant in 1989, and will accept approximately 5.000 cubic yards of this sludge on a yearly basis. The sludge is currently being stockpiled at the landfill. The sludge may be used in the foundation layer of the final cover. The first water bearing formation is approximately 70 feet below the base of the landfill, with the hydraulic gradient to the north/northeast. The beneficial uses of ground water are domestic, municipal, and agricultural. The facility receives an average of 14 inches of precipitation per year, with the 100 -year, 24-hour precipitation event of 6.17 inches. Pacific Energy Inc. operates a methane gas recovery system under contract with the City of Stockton. The methane is used in a power plant to generate electricity. The gas recovery system has an estimated life of 15 to 20 years. A Solid Waste Assessment Test was performed at the facility as required by Water Code Section 13273. The results of the test show that there has been a significant water quality impact to ground water. The following volatile organic compounds (VOCs) were found in the downgradient monitoring wells: vinyl chloride (11 µg/1), tetrachloroehene (210 )Ug/1), trichloroethane (39 µg/1), and cis -1, 2-dichloroethane (36 µg/1), and numerous others. This was confirmed with further sampling. Supplemental sampling results indicated that VOCs were detected in California Youth Authority (CYA) wells CYA-1 and CYA-2 at levels equal to or slightly above action levels. However, confirmation sampling of the CYA wells did not detect any VOCs. Sampling at a private well at 8106A Austin Road did find VOCs. and this was confirmed by further sampling. Because of the detection of volatile organics in the ground water downgradient of the landfill, an evaluation monitoring program was implemented to determine the nature and extent of the