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✓ Investigate the current groundwater conditions under the property, and water chemistry from the on-site well water, specifically the nitrate concentration, sodium concentration, and the suitability for agricultural irrigation. Environmental Health Department staff requested that the agrichemical Dibromochloropropane (DBCP) not be analyzed since this material was never used in this locale. ✓ Estimate potential nitrate impact from future septic systems on the proposed residential development of the subject property. Attempt to identify past and present sources of nitrate impacting the underlying groundwater and discuss potential impact from historical upgradient agricultural production. ✓ Discuss mitigation measures to alleviate nitrate loading from the septic systems proposed for this development. II. SOIL SUITABILITY STUDY FINDINGS A. SUBJECT PROPERTY AND SURROUNDING STUDY AREA INFORMATION The sketch plat for Certificate of Compliance, found in Appendix 1, produced by Aspen Survey illustrates the orientation of the three subject parcels. As evidenced by the United States Department of Agriculture (USDA) Soil Map of San Joaquin County for this area produced in the 1970s, and the USGS Map, the historical land uses surrounding the property include agricultural production to the east, west and north. To the south, the land appears to be predominately fallow. The subject property at present, is completely fallow. There is a recently installed domestic well in the southwest corner of Parcel 2 and vinyl fencing surrounds and delineates each of the three parcels. Applications on file with the County Environmental Health Department indicate that there have been no permits issued for repairs/additions to existing septic systems in the one-half mile study radius. This can be attributed to the extremely low septic system density surrounding the property. From discussions with EHD staff, it is known that septic systems installed in this locale typically include leachlines with seepage pits, and it may be that seepage pits manage most of the effluent in this area due to the poor shallow soil structures. B. SOIL PHYSICAL AND CHEMICAL CHARACTERISTICS The project site has level terrain; consequently, there will be no need to incorporate design considerations for slopes. The United States Department of Agriculture - Natural Resources Conservation Service (USDA-NRCS) shows the on-site soils to consist of Zacharias gravelly clay loam (#282), with a very small portion of soil in the SEC of the property to be Xerofluvents- Xerothents complex (#278). According to the USDA Handbook,the surface layer of the Zacharias soil is a dark brown gravelly clay loam about 14 inches thick. 2 Chesney Consulting