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November 16,2005 <br /> • NOA Project Number: E05120B <br /> 1.3 Geology <br /> According to the Geologic Maps of the Sacramento-San Joaquin Delta, California,'the Site is <br /> located on a map unit identified as alluvium from creeks of the Corral Hollow drainage to Brushy <br /> Creek (Holocene and/or upper Pleistocene). Alluvium consists of mixtures of sand, silt, and clay <br /> deposited by erosional processes which form soil in valleys. <br /> 1.4 Topography <br /> Based on a review of the most recent USGS topographic map for the area,'it appears that the Site is <br /> located between 80 and 125 feet above mean sea level. Topography in the vicinity of the Site slopes <br /> down to the northeast at a rate of approximately 90 feet vertical per mile horizontal. <br /> 1.5 Regional Groundwater <br /> The Site is located in an area for which groundwater depth and gradient are not mapped by the San <br /> Joaquin County Flood Control and Water Conservation District. Groundwater typically flows to the <br /> northeast in the southwest portion of San Joaquin County. Bruce Kimbrough,operator of the dairy, <br /> confirmed that on-site groundwater flows toward the northeast corner of the Sites It is likely that <br /> regional groundwater gradients follow the patter of regional topography. <br /> • 2.0 WORKPLAN, PERMITS,AND SAFETY <br /> Prior to start of work, a workplan was submitted to and approved by the EHD,and all necessary <br /> drilling permits were obtained (permit#0044192). A check for any existing underground utilities <br /> was conducted at the drill location. Also,a brief"tailgate safety meeting" was conducted to inform <br /> the field crew of anticipated hazards and the emergency action plan for the site. On-site workers <br /> used Level D personal protective equipment. <br /> 3.0 SURFACE STAINING INVESTIGATION <br /> 3.1 Sample Locations and Collection Methods <br /> Surface samples (0 to 6 depth)were collected from nine discrete locations in and around the shop <br /> building and garage. The sample locations are depicted on Plate 2. Sample collection locations <br /> 3Atwater,Brian F.,Geologic Maps of the Sacramento-San Joaquin Delta,California,Clifton Court Forebay <br /> quadrangle,1982,USGS MF-1401,Scale 1 in= 2,000 ft. <br /> 4U Geological Survey,1999,7.5'Topographic Map of Clifton Court Forebay Quadrangle,obtained from <br /> Microsoft Terraserver. <br /> 5Personal Communication,September 6,2005. <br /> • 3 <br />