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k'9 KLEINFELDER • 2.3. REGIONAL GEOLOGY AND HYDROGEOLOGY The site lies within the central potion of the Great Valley Geomorphic Province of California. The valley is approximately 400 miles long and averages about 50 miles wide, and comprises about 20,000 square miles. The valley has been filled with a thick sequence of marine and non-marine sediments from the late Jurassic to Holocene. The uppermost strata of the Great Valley represent, for the most part, the alluvial, flood, and delta plains of two major rivers (Sacramento and San Joaquin Rivers) and their tributaries. The valley deposits are derived from the Coast Ranges to the west and the Sierra Nevada to the east. Granitic and metamorphic rocks outcrop along the eastern and southeastern flanks of the valley. Marine sedimentary rocks outcrop along most of the western, southwestern, southern, and southeastern flanks; and volcanic rocks and deposits outcrop along the northeastern flanks of the valley. The valley geomorphology includes dissected uplands, low alluvial plains and fans, river flood plains and channels, and overflow lands and lake bottoms. The majority of the native sediments near the site consist of Miocene to Holocene continental rocks and deposits of a heterogeneous mixture of generally poorly sorted clay, silt, sand, and gravel. Some beds of claystone, siltstone, sandstone, and conglomerate are also present. • Based on the SJCFCWCD, Lines of Equal Elevation and depth to Groundwater Map, 2003, groundwater in the vicinity of the site is anticipated to occur at approximately 80 to 0 feet bgs.generegional erally toward heno heast withgroundwatergroundwatertion of g ou dwaterdepressions noted north, east, and west of the site. • Page 5 of 20 63138.H01/ST06R312/JDZ:ly April 7,2006 ©2006 Kleinfelder, Inc.