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application practices, it is possible that environmentally persistent pesticides were historically stored or mixed proximate to barns, sheds, or outbuildings. 3.0 GEOLOGY AND HYDROGEOLOGY A topographic map of the Site area is shown on Figure 1. Regional and local geology and hydrogeology are summarized in an October 2007 document titled Groundwater Management Plan for the Northern Agencies in the Delta-Mendota Canal Service Area and a Portion of San Joaquin County, prepared by Boyle Engineering(Boyle). Boyle's report cites numerous municipal and agency documents including those from the United States Geological Survey and the California Department of Water Resources' 2003 Update of Bulletin 118, titled California Groundwater. The following statements are based on citations within Boyle's report. The Site is located with the San Joaquin River hydrological region, specifically within the San Joaquin Basin and the Tracy Subbasin. The beneficial uses of groundwater in the area are predominantly for agriculture and related industry, domestic potable water, and other municipal uses. Groundwater is generally used conjunctively to supplement surface water supplies that support the water needs in the area. The San Joaquin Valley is the southern portion of the Great Valley Geomorphic Province in central California. The San Joaquin Valley is a structural trough up to 200 miles long and 45 to 70 miles wide. It conjoins the northern portion of the Great Valley Geomorphic Province, the Sacramento Valley, at the confluence of the Sacramento and San Joaquin Rivers ("the Delta"). The Great Valley opens to the San Francisco Bay west of this Delta. The San Joaquin Valley is bounded by the Sierra Nevada to the east, the Coast Range to the west, and the Tehachapi Mountains to the south. It is a broad, fault bounded, northwest trending, asymmetric topographic and structural trough, with axis of the valley offset nearer the western margin. The topographic slope along the axis declines gently, generally towards the north- northwest. Within the western San Joaquin Valley, the land surface generally slopes easterly to northeasterly from the base of the Coast Range,near the western boundary,towards the trough of the valley and the San Joaquin River. Small ephemeral streams drain from the Coast Range Mountains typically trending northeasterly toward the trough of the valley. The natural land surface is relatively flat to slightly undulating. The geologic materials that fill the San Joaquin Valley comprise mostly unconsolidated alluvial and lacustrine sediments, Holocene to Jurassic in age, derived from parent materials of the Coast Range and the Sierra Nevada; these sediments are overlying older marine sediments. Continental Sampling and Analysis Workplan Tracy Corners Shopping Center 3225 North Tracy Boulevard Tracy,California 95376 Partner Project Number SM14-129814 Docket Number HAS-VCA 14/15-108 August 15,2016 Page 11