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r7t). GROUNDWATER INFORMATION Groundwater depths and elevations are illustrated on maps published by the San Joaquin County Flood Control and Water Conservation District. The 1999 Lines of Equal Depth map illustrates the groundwater depth under the subject properties to be approximately 45 feet below grade. The static water level was measured in Mr. Calkins domestic well to be 50 feet below grade. Lines of Equal Elevation map in 1999 show the groundwater to be at an elevation of 10 feet MSL and the directional flow to be north-northeast. This corresponds with data collected from the Goehring Meat Company processing plant, which indicates a contaminant plume that originated from this facility is moving in a north-northeast direction. The groundwater gradient as determined by the Lines of Equal Elevation Map is 5 feet_0.75 x 5,280= 0.0013 ft/ft. Based upon studies with similar groundwater gradients, the velocity of the groundwater under the subject property can be roughly estimated to be approximately 60 feet/year. For comparison purposes, the Lines of Equal Elevation map of 1992 show the water table elevation to be 0 feet MSL. The United States Geological Survey map has surveyed the elevation of the property to be 55 feet MSL, which would place the water table at 55 feet below ground surface ten years ago. Therefore,the water table has risen between five and ten feet in the last decade. The critical issue regarding the groundwater elevation is there must be sufficient distance between the bottom of a leachline trench, or seepage pit and the highest anticipated depth to groundwater for sufficient treatment of the septic effluent to occur. This is generally accepted to be five feet in leachline trenches and ten feet in seepage pits. Therefore, sufficient distance currently exists between these structures and the static water table depth. The water table would have to rise another 10 to 15 feet before the separation distance between the bottom of a seepage pit and the water table would be violated. GROUNDWATER ANALYTICAL TEST RESULTS To test the underlying groundwater for the Soil Suitability Study requirements, well water was obtained from three wells owned by Mr. Calkins. One of these well is on the subject property and the other two are on Mr. Calkin's residential parcel. As noted in the Table below, at present, the underlying groundwater has a medium nitrate concentration. These test results are interesting in that higher nitrate concentrations would have been expected given the intense agricultural production in this region. Secondly, a greater disparity would have also been expected among the three wells given the differences in depths. Since the wells were installed in the late 1950s, no record of their construction details was available. 7 Chesney Consufting