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.. .e Spiess Rancho Soil Suitability Study Page No. 3 V. GROUND WATER DEPTH AND TESTING According to the map of "Lines of Equal Depth to Water in Wells" published spring 1994 by the San Joaquin County Flood Control and Water Conservation District, the depth to groundwater at this location is between 75 and 85 feet. _ There is a domestic water well located at the residence on proposed parcel 22, and another domestic well located at the diary barn on proposed parcel 23 . These two wells were sampled on May 12, 1995 and tested for the presence of nitrates and dibromochloropropane (DBCP) . Test results indicated that DBCP was non-detected at each well, and the level of nitrate was 14 mg/l at each well, which is well below the Maximum Contaminate Level (MCL) of 45 mg/1. A copy of the test results are included in the Appendix. VI. SOIL PROFILE AND PERCOLATION TESTS Forty-three test holes were excavated to a depth of 15 to 25 feet in the areas of the proposed homesites in order to determine the soil profile in the general area. For approximate location of the test holes (PT) see the Parcel Map in the Appendix. The test holes were logged by an engineer and a description of the soils encountered in each hole is contained in the Appendix. The surface soils generally consisted of a brown sandy silt or sandy silty clay. The surface soils were underlain by hardpan; a moderately cemented layer of brown sandy silt. For a more detailed description of the soils encountered see the log of test holes. Deep pit ( 10 to 25 feet deep) percolation tests were performed at each of the test hole locations. Test were performed in 4. 5 inch diameter holes excavated to the depth indicated. Two 2 inches of gravel was placed in the bottom of each hole and a 2 inch diameter perforated pipe was placed and backfilled with gravel. Each of the tests holes were presoaked with water 24 hours prior to running the tests. The last half hour of the tests readings were witnessed by a county health official and the test data obtained is enclosed in the Appendix. The percolation rates have been adjusted to account for the gravel and pipe backfill. Calculations for adjustments are on the test data sheets. A summary of the test rersults are presented in Table 1, Deep Pit percolation Test Results. Y pER50� D '^ Q ~ SSS OGS P