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(§ 4.0) LOCAL GROUNDWATER AND SURFACE WATER INFORMATION (§4.1) The 1999'Lines of Equal Depth Map published by the San Joaquin County Flood Control illustrates the groundwater depth to be approximately 12-13 feet below ground surface (b.g.s.). The 1999 Lines of Equal Elevation Map illustrates the groundwater directional flow to be most likely in a westerly direction toward the San Joaquin River and the Delta. Well Drillers' Logs for nearby domestic wells were not found in the microfiche files at EHD. Therefore, the underground lithology specific to the subject property could not be discerned. Regarding the property being subj ect to 100-year flooding will be based upon Wong Engineers' determination. Surface water runoff will be diverted into the surrounding orchard. (§4.3 and 4.5) The first well sampled was the eastern ag well. This well was allowed to pump water for 15 minutes to ensure the sampling of aquifer formation water. The nitrate sample was taken from the PVC pipe outlet before the water entered the concrete standpipe. The second well sampled was the domestic well that serves Consuelo Noceti's home. This sample was taken from the sample port on the cast side of the outlet pipe. This well was also allowed to pump for 15 minutes to ensure the sampling of aquifer formation water, and was tested for both nitrate and r DBCP/EDB. (§ 4.6) A clear plastic bottle was used for the nitrate samples and two amber VOC bottles with preservative were used for the DBCP/EDB samples. The samples were placed in a cooled ice chest and transported under the attached Chain of Custody to A &L Labs in Modesto, California to be analyzed for nitrate, Dibromochloropropane (DBCP), and Ethylene Dibromide (EDB). (§ 4.2 and 4.4) Water analysis reveals a high nitrate (as nitrate-NO3) concentration of 71 ppm for the eastern ag well and a very high concentration of 132 ppm nitrate for the domestic well. DBCP and EDB were found to be Below Detectible Limits (BDL). The Maximum Contaminant Level (MCL) for.nitrate in drinking water is 45 ppm. This lower 71 ppm nitrate concentration found in the ag well maybe attributed to: 1.)Nitrate impact primarily occurring at the higher elevation aquifers where the domestic well is screened, 2.) Comparable nitrate concentrations have not percolated down to the deeper aquifers yet, 3.) There may be.intervening clay soil strata below, attenuating downward nitrate movement, or 4.) There is significant denitrification potential within the underlying aquifers, especially at the deeper depths. F (§ 7.0) CONCLUSIONS The perc test results for proposed Parcel 1 and Parcel 2 show acceptable percolation for the management of anticipated septic system effluent flows. For Parcel 1, effluent management from the new residential structure will occur at the typical leachline trench depth of 42 inches. This also applies to any structure built on Parcel 2 in the future. As noted from the pert test results, as the soil becomes saturated,percolation potential decreases. Page -4- Chesney Consulting