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Alk <br /> h� KLEINFELDER <br /> 4 SITE HYDROGEOLOGY <br /> The site is nearly flat, and located at an approximately elevation of 30 feet above sea level. The <br /> USGS 7-1/2 minute Union Island quadrangle shows a downward slope of the natural topography <br /> to the north. The San Joaquin County Water Conservation District map entitled "Lines of Equal <br /> Elevation of Water in Wells" for Fall 1991 shows the water table at approximately 20 feet above <br /> sea level with a decreasing water table elevation to the north. <br /> Surficial geology at the site, as interpreted from borings installed by Kleinfelder to date consists of <br /> a clayey silt with intermixed fine sand from the surface to depths ranging from 1-1/2 to 4 feet <br /> below existing grade. Below this was clayey silt to approximately 9-1/2 to 11 feet. At 9-1/2 to <br /> 11 feet the lithology grades to a loose, fine to medium sand that alternately includes either silt at <br /> the east or west edges of the area investigation (NIW-2, and MW-3) or fine gravel towards the <br /> middle (EW-1 and MW-1) of the area. The sand zone is quite loose at depth, causing "heaving <br /> sand" problems during well installation. During drilling, groundwater was first encountered from <br /> 12 to 13 feet below grade. <br /> 24-220176-FOI/CR43-8 (1994) Page 8 of 13 June 3, 1994 <br /> Copyright 1994 Kleinfelder, Inc. <br />