ARCHIVED REPORTS_ENVIRONMENTAL SITE ASSESSMENT

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The Stockton West Quadrangle Map shows no physical features that are likely to environmentally impact the subject property. The subject property is identified as developed with the existing industrial structure (served by a railroad siding), located within an area of partially developed (pink, purple, black) and undeveloped land (white). The building was constructed some time between 1957 and 1963 as evidenced from aerial photographs (PEI 2010). No mines, wells, aboveground storage tanks, or wetlands were depicted in the immediate area of the subject property. A small canal is noted immediately beyond Industrial Drive to the north but no other wetlands are adjoining. In addition, a large industrial building and a feature labeled "Industrial Waste Ponds" exist about one-half mile to the southeast. The elevation of the subject property is approximately 15 feet above mean sea level with a subtle topographic gradient toward French Camp Slough to the west-northwest. C. LOCAL AND SITE GEOLOGY The subject property is located within the Sacramento Valley, which consists primarily of river- borne alluvium extending from the Sierra Nevada Mountains on the east to the Coast Ranges on the west. The subsurface features of the valley are related to erosion of the surrounding hills and mountains, resulting in the deposition of deep layers of alluvial deposits. The soils beneath the site are interpreted to be alluvial/fluvial deposits that are the result of flood events and overbank deposits from local sloughs. The predominant soil type is bioturbated (roots and burrowing), very dark brown and gray clayey silt to the drilled depth of 50 feet bgs. These soils contain caliche in the form of blebs and stringers but not as a well- indurated and thick layer. Almost all of the soils are oxidized to a brown or reddish brown color as a coating. Sand-sized soils are rare but tend to exist around 26 to 28 feet bgs if they are present. Above the sand the silts have a yellow brown color. D. LOCAL AND SITE HYDROGEOLOGY Although site-specific groundwater information for the subject property was unavailable, the State Water Resources Control Board's online Geotracker database (www.geotracker.swrcb.ca.gov) identified the closest LUST site with available online groundwater data (H & H Engineering and Construction facility at 212 Industrial Dr., the western adjoining property). There, the reported depth to first groundwater ranged from approximately 27 to 38 feet bgs between 1999 and 2007. The available online data also indicate a general northeasterly direction of groundwater flow at that site (toward the northwest portion of the subject property). However, local groundwater can be influenced by several factors, and may not conform to the reported nearby pattern. Shallower groundwater zones may occur. Groundwater was encountered in all four temporary groundwater monitoring wells installed during this investigation. Although saturated sands were encountered at the 27-ft bgs depth, it required another 2 to 20 ft of drilling to encourage flow into the boreholes. Groundwater recovery was slow in all wells but GW-1, which was drilled to 50 feet. Static groundwater was measured to be 27 feet bgs in each well Limited Phase II Environmental Site Assessment Report Pinnacle Environmental,Inc. 248 Industrial Avenue,Stockton,CA 95206 Page 8