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SOIL SUITABILITY STUDY, ACAMPO ESTATES Page No. 4 V. GROUND WATER DEPTH AND TESTING According to the map of "Lines of Equal Depth to Water in Wells" published fall 1990 by the San Joaquin County Flood Control and Water Conservation District, the depth I` to groundwater at this location is approximately 80 to 90 feet. There is a dom6stic/agricultural well on the subject property located just south of the hay barn. A water sample was obtained from this well on December 5, 1991. A second sample was obtained:,from a domestic well located near the NW corner of the subject property. Both samples were submitted to the laboratory for testing. The samples were tested for the presence of nitrates and dibromo chloropropane (DBCP), which is a soil fumigant used in vineyards. A copy of the test results is contained in the Appendix. The results of the tests indicate that the nitrates were well below the MCL (maximum concentration limit) allowed by law and DBCP was not detected. VI. SOIL PROFILE AND PERCOLATION TESTS i Three test borings were made in order to determine the soil profile in the general area and in preparation for running the deep, pit percolation tests. Test boring were carried to depths of 20.0 to 25.0 feet. For approximate location of the test borings see the Location Map in the Appendix. The test borings were made with a Mobile B-53 Explorer drill rig utilizing 8 inch hollow stem auger. Soil samples were obtained at periodic intervals to aid in classifying the various soil strata encountered. The test holes were logged by a civil engineer. A description of each soil encountered is presented in the Appendix as Log of Test Holes. The surface soils encountered in the test holes consisted of a 0.5 to 2.0 foot stratum of sandy to clayey silt that was underlaid by a rather thick, 7.5 to 12.5 foot, stratum of cemented silty sand (hardpan). Due to the cemented nature of this material, percolation rates of it would be very low and unsuitable for the installation of a shallow leach field only. In test holes 1 and 3,` the cemented material was underlaid by a stratum of fairly clean, medium dense sand that would provide reasonable percolation. In test hole 2, a clay i stratum and more cemented stratums were encountered to the maximum depth explored, however, it is likely that some uncemented sand lenses exist within the cemented strata. For a more detailed description of the soils encountered see the Log of Test Pits. A total of 6 percolation tests were performed, 2 at each test hole location. One of the tests at each location was a shallow (36 inch deep) percolation test and the other was ; a V� Rsoy. ; n Z w a h 4SSOG� P