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groundwater within these two formations is saline and is separated from the above fresh water bearing units by an impermeable bed within the upper Mehrten Formation. The unconsolidated units consist of alluvial sediments of the Victor Formation, Arroyo Seco Grave- and the Laguna Formation. These formations are composed of gravels, sands, silts and clays with intervals of hardpan and have a total thickness of 1100 `pet. Good quality groundwater is present under generally unconfined aquifer conditions although minor confined aquife= a ;xist. A berrier to saline groundwater intrusion occurs along the west side of Stockton and is formed by a depositional contact ` between the deltaic deposits to the west and the alluvial deposits to the east. The unconsolidated deposits directly beneath the study site varied from clays to sandy gravels. A review of the drilling logs for the 9 monitoring wells indicated thzt the site is blanketed by a surfacial silty to sandy clay which varies between r� 2 to 12 feet in thickness. The clays grade into a sandy interval which becomes increasingly coarse with depth. Between 30 to 34 feet below grade. The sands are underlain by a dominantly clay k interval which increases in stiffness with depth. This clay extends to 50 feet below the ground surface, the maximum depth explored (Appendix I). The Cross Section Index Map (Figure 4) shows the location of Gross-Section A-A (Figure 5) which graph- ically depicts the trends noted above. Groundwater was initially present at approximately 30 feet 1 below grade in May 1986 but has lowered to greater than 33 feet M through August 1986. The groundwat�..r appears to flow in a southeasterly to easterly direction. The closest surface water bodies are an un--named creek 700 feet to the southeast and Mosher Slouch 1506 feet to the south. 7