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M in the 35 to 40 foot zone below the surface. This zone contains a silt which is common throughout the site. The figure shows the general trend in the vadose contamination is to the south- southeast. Apparently there has been no vadose migration to the north and only slight movement to the east and west. In early 1990, the water table was located at 44 feet below the surface. In wells 1, 4 , and 5 we found fuel contamination at 40 feet and below. This area is contaminated because it was the capillary fringe at one time. The distribution of contamination at the 40 foot level and below is caused by the movement of groundwater. Although this zone is unsaturated at present it could become saturated again. Wells BM-2 , 3 , and 6 had no contamination at all and their position defines the zero line along the west and north sides of the site. Well 5 has a small amount of contamination at 15 feet but the fact that the zones below 15 feet are clean to the 40 foot level indicate the northern migration of fuel in the unsaturated zone was very limited. Therefore, we assess the northern limit of the contamination is 3ust beyond BM-5 . • Groundwater The site at present has two hydraulic gradients the principal one to the northeast and a slight secondary one to the southwest near well BM--7 . In 1990 the gradient was to the northwest. Recent groundwater maps of the area (San Joaquin County Flood Control 1991 and 1986) indicate a regional hydraulic gradient toward the east. The wells installed recently were designed to have one of the wells down gradient and one up gradient. Measuring the water • table resulted in two gradients present at this time. However, . we believe well BM-7 will become an up gradient well by the time Page 6 •