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07/13/,,2006 08:24 FAX R008/028 KI The r.;sults of the groundwater analysis to determine the concentrations of nitrate (N) in the water sampled from the on-site well indicated a concentration of 14 mg/t. This nitrate. concentration is not below the state drinking water standard of 10 mg/l. DBCP was not present in detectable amounts. Copies of the test results and the chain--of- custody are presented on Plate 8. We do not know of any existing and/or potential groundwater contamination issues in the project vicinity_ There are no existing gas stations or ,fairies adjacent to the property. Seasonal fertilization of the off-site agricultural land, if performed, and other septic tank/leach field systems in the project area are probably the largest contributor of nitrogen to groundwater in the project vicinity. 7. _301L PROFILE The subsurface soil encountered in our soil profile boring consisted of brown, fine grained silty sand to a depth of approximately 6 feet below site grade, followed by fine grained relatively "clean" sand to a depth of about 12%2 feet. The sand was underlain by sandy silt to a depth of about 13'/2 feet, followed by a strata of silt clay to the depth explored. y y P The Soil Survey of San Joaquin County, California published by the U.S. Department Of Agriculture, Soil Conservation Service (1992) refers to the near-surface soil within the western area of the project as belonging to the Bisgani Loamy Coarse Sana soil series (Map Symbol 109) and the soil within the eastern area of the project as belonging to the Tinnin Loamy Coarse Sand soil series'(Map Symbol 255). €his soil is described as (laving "moderate" percolation characteristics for septic tank absorption. Other attributes are given in the table below: Map ; l Available Yater Organic "�y�lt. rol Sail Name ; Capacity, Pkv incheslinch Content, percent 103 isgahi loamy 0.06-0.08 7.4-8.4 1-3 Coarse Sand 255 Tinnin Loamy t __ ........._.._ _._�............ 1 0.05-0.07 6.1-7.8 1-2 ; Coarse Sand i i € 8. PERCOLATION TESTING The re;ult Of our percolation test is presented below. A copy of our field percolation test result is attached. Test Soil i Test Hole Percolation Rate SJCEHD Number Eescrl tion . � ..._..._.,.,..... ...._. ©el�#E• nilEi.11l7Gl7 Aroved P-1 Silty Sand 3.2 7.7 __ --................_.. Yes 71 324-Gp>lST06R759 .lull.1.1,2006 C:,anyr�gnt:?0�}e KI+�rs4rrid+r.Irr.. N��Ea v{9 l