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i J 1 November 1990 -7- M88168D I SITE HYDROGEOLOGY The site is located within the Great Valley ground water basin of California which is a highly complex ground water basin that extends from the town of Red Bluff on the north, south some 400 miles to the city of Bakersfield (State of California, Department of Water Resources, 1974, p. 1) . Subsurface water was encountered during this assessment at depths of approximately 64 and 90 feet bgs (elevations of approximately 14 and 40 feet below mean sea level [MSL] , respectively) . Ground water is defined as subsurface water occurring in the zone of saturation (below the water table) and moving under control of the water table I slope or gradient. Below the ground surface there are two zones: an unsaturated zone and a saturated zone. The unsaturated zone is that zone between the land surface and the water table and includes the capillary fringe. Perched water bodies may exist within the unsaturated zone. The saturated zone is that part of the water bearing material in which all voids, large and small, are filled 1 with water. A perched water body was encountered at a depth of 64 feet at MW-1 (refer to Plate A-1.1) . This perched water body extended from the depths of 64 to 67 feet within the unsaturated zone. Because of mechanical limitations of the drill rig, the subsurface water encountered at a depth of 90-feet at DH-2 was not able to be positively identified as ground water within the ground water table. From this information, we can infer that ground water exists at the site at a depth of greater than 90 feet bgs (elevation of -40 feet MSL) . Because adequate ground water monitoring wells were not able to be constructed at this site, a model of the ground water surface beneath the site was not calculated. SOIL CONTAMINATION The analytical results of the soil sample collection program are summarized in Table 1 - Analytical Results of Soil Samples, and are presented in IAppendix B. The analytical results of the soil samples analyzed indicate that contamination concentrations in excess of DOHS standards do not exist within the � i area assessed, based on the analytical method employed. Where detected, total l