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Coca-Cola Enterprises - West lob No. 90054 fill the valley, the original form of a deep trough is still present in the basement Sierra granite. During Mesozoic time, land sediments and oceanic deposits were mixed and partially metamorphosed. After Tertiary time, the valley was most influenced by the San Andreas fault system to the west. As a result of this faulting and the continued accumulation of sediments ~ in the valley, the ground surface elevation is sUght!y higher than sea level (about 15 to 20 feet). The Stockton area is underlain with thick alluvial deposits of silt, sand, and clay. Due to the interfingering of some of these deposits, along with a series of other alluvial deposits, terraces �- and fans, the alluvial sequence is thought to reflect a deltaic depositional environment. eluvial deposits thousands of feet thick have filled the valley and hold the groundwater used in the _ Stockton area. Groundwater drawdown in the Stocktoi,metropolitan area has been substantial , up to 20 feet or more in the last 5 years and is partially due to the drought conditions of the last three years. Groundwater elevations in the city area exceed -50 feet below sea Ievel. F 6.2 SITE PHYSIOGRAPHY `µ The San Joaquin valley is characterized by a moderate climate,with a mild, rainy winter season Lam. with fog, and moderate to hot dry summers. The mean annual temperature ranges from 65 to �.� 75 degrees Fahrenheit. Precipitation ranges from 13 to 14 inches annually, occuring primarily i in winter months. i 6.3 SITE SPECIFIC GEOLOGY The stratigraphic sequeaces beneath the site are identified on the boring logs and in a stratigraphic cross-section. The cross-section locational line is shown on Figure 10. The cross- section A - X is illustrated on Figure 11. The geologic Iogs completed during the drilling Analysis of the boning logs and the cross-section process are presented in Appendix C. indicates that the sediments underlying the site are predominantly sands, silts and clays which have been deposited by fluvial processes. The site is generally underlain by clay and silt, however there are clean sand, silty sand, and clayey sand lenses throughout the underlying strata. It is thought that these strata are delta deposits and thus exhibit little to no continuity across the site. As seen from the cross section ! on Figure 11, layers are not continuous, which indicates complex interfingering of the strata. 15 Rei