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h� KLEINFELDER 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. Site specific geologic information was obtained from two documents prepared for Spreckels Sugar by Kenneth D. Schmidt, Groundwater Quality Consultant (Schmidt 1985 and Schmidt 1993). The documents are technical reports on groundwater monitoring efforts associated with the wastewater, lime and mud ponds on site. According to Mr. Schmidt, coarse-grained alluvial deposits, primarily fine to medium grained sand, are present to a depth of at least 60 feet below grade. Localized clay strata are also present in the upper 60 feet. Additionally, two major clay layers are present beneath the site at approximate depths of 95 to 141 feet, and 188 to 243 feet. Mr. Schmidt identifies the deeper clay layer (188 to 243 feet) as the Corcoran Clay, a major regional confining bed that occurs along the west side of the San Joaquin Valley. Water level information was also obtained from the Schmidt groundwater reports in addition to numerous Kleinfelder documents. Generally, during the period of the monitoring (1992 to date) the groundwater elevation beneath the former Spreckels factory site ranged from 17 to 28 feet above mean sea level. The direction of groundwater flow was predominantly to the west- northwest. Historical groundwater information obtained by Mr. Schmidt indicates that in 1950 depth to groundwater beneath the factory was 10 feet with a direction of groundwater flow to the west. Depth to groundwater in the vicinity of the site has historically ranged from 10 to 30 feet below grade, with groundwater flow directions varying from due west to northwest. 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. The general direction of groundwater flow in the area of the site, based on a report issued by the San Joaquin County Flood Control and Water Conservation District, Spring 1995, and is to the northwest. The elevation of first groundwater is approximately 20 feet below mean sea level. According to the same report, the depth to groundwater in the vicinity of the project site is approximately 20 feet below grade. 3.0 BACKGROUND Kleinfelder has conducted a Phase I Environmental Site Assessment (ESA) of the property known as the Former Spreckels Sugar Plant in Manteca, California (Kleinfelder Job No. 20- 3978-OLP01, dated October 18, 1996). The following process description was compiled during that assessment. Plate 1 shows the location of the Spreckels property. 20-Y PO-273/2000P331/2000 W 034 Page 3 of I I Copyright 2000, Kleinfelder,Inc. September 4,2000