CORRESPONDENCE_1991-2001 - Laserfiche WebLink

Home Browse Search

WASTE DISCHARGE RobIREMENTS ORDER NO. -2- SAN JOAQUIN COUNTY FOR POST-CLOSURE AND CORRECTIVE ACTION MONITORING CORRAL HOLLOW SANITARY LANDFILL SAN JOAQUIN COUNTY 7. The 100-year, 24-hour precipitation event is estimated to be 2.3 inches, based on Department of Water Resources calculations from precipitation readings collected at the Tracy 2 SSE weather station. 8. The toe of the southern slope of the waste management facility is within a 100-year flood plain based on the Federal Emergency Management Agency's (FEMA) Flood Insurance Rate Map, Community-Panel Number 0715A 060299. 9. The 1988 SWAT report shows two water supply wells located within a 1-mile radius of the landfill. One is an industrial supply well approximately 1-mile northeast of the landfill at the gravel pit south of the Tracy Municipal Airport. The other is a domestic supply well located approximately 1000 feet northeast of the landfill on the east side of Corral Hollow Road. A 1986 Kleinfelder report also shows two other wells that appear to be within the 1- mile radius, located to the southwest of the landfill. WASTE AND SITE CLASSIFICATION 10. The Discharger discharged municipal solid wastes, which are defined in §20164 of Title 27. SURFACE AND GROUND WATER CONDITIONS 11. The Water Quality Control Plan for the Sacramento and San Joaquin River Basins, Fourth Edition (hereafter Basin Plan), designates beneficial uses, establishes water quality objectives, and contains implementation plans and policies for all waters of the Basin. 12. Surface drainage is toward Corral Hollow Creek,which flows easterly in the North Diablo Range Hydrologic Unit(543.00) of the San Joaquin Hydrologic Basin. 13. The landfill is on the alluvial fan at the mouth of Corral Hollow Creek at the base of the eastern side of the Coast Range. Corral Hollow Creek is an intermittent stream that flows toward the San Joaquin River, but the flow dissipates into the alluvium south of Tracy. The designated beneficial uses of Corral Hollow Creek as tributary to the San Joaquin River, as specified in the Basin Plan, are municipal and domestic supply, agricultural supply, industrial service and process supply, and water contact recreation. 14. The first encountered groundwater on the eastern half of the landfill ranges from about 14 to 68 feet below the native ground surface because of the variation in topographic relief. Groundwater elevations range from 233.5 feet MSL to 229 feet MSL. The groundwater is unconfined and mounds near monitoring well SB-1. The shallow,perched aquifer is not laterally extensive to the western half of the landfill, however laterally groundwater was encountered at depths greater than 250 feet. Three groundwater monitoring wells are constructed within the deeper flow zone to a depth of 329 feet below ground surface (bgs), but groundwater has not been present within these three wells since 1990.