COMPLIANCE INFO_1993-1994 - Laserfiche WebLink

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City of Stockton TL# 394-0027-01 March 10, 1994 Page 2 3. 1 Site Description The Austin Road Landfill (site) , a municipal waste collection center, is located southeast of the city of Stockton, California immediately west of the intersection of Littlejohns Creek and Austin Road (Drawing 1) . The site is located in the north half of Section 3, Township 1 South, Range 7 East Mount Diable Baseline and Meridian. 3 .2 Geologic and Hydrologic Characteristics 3.2 . 1 Geology The site is located in the northern portion of the San Joaquin Valley which comprises the southern segment of the larger Great Valley. The Great Valley is an asymmetrical synclinal trough interrupted by two major surface cross structures : the Stockton fault in the Stockton arch and the White Wolf fault in and south of the Bakersfield arch. The Stockton fault is located approximately five miles northwest of the site, trending northeast. The Great Valley has been filled with a sequence of older to younger alluvium of Pliocene to Holocene age which overlie sedimentary rocks of Cretaceous to Tertiary age. These sedimentary units, in turn, overlie a crystalline basement of Paleozoic and Mesozoic metamorphic and igneous rocks. The shallow subsurface geology in the site vicinity consists of a heterogeneous mix of gravel, sand, silt, and clay (Norris and Webb, 1990) . 3.2 .2 Hydrology Sediments containing fresh groundwater are largely unconsolidated silts and sands derived from river channel, flood plain, and alluvial fan deposits of Pliocene to Recent age (Davis and others, 1959) . First encountered groundwater in the site vicinity occurs under unconfined (water table) conditions at a depth of approximately 80 to 90 feet BSG and generally flows to the southeast. Local groundwater flow may be influenced by pumping of water wells and recharge from various sources. The effect of these influences on groundwater beneath the site is beyond the scope of this investigation. 3.3 Project History The Austin Road Landfill has been used as a municipal waste dump. The existing groundwater monitoring wells were installed by Kleinfelder Associates. During fourth quarter monitoring in 1993, two wells were found to be dry.