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r��(§4.2 and 4.4) Water analysis reveals a very low nitrate (as nitrate -NO3) concentration of<2 ppm for the irrigation well, and a very low concentration at 2 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. These very low nitrate concentrations found in both the irrigation well and the domestic well may be attributed to: 1.)Nitrate impact may be primarily occurring at the higher elevation aquifers where these wells are not screened, 2.) Higher nitrate concentrations have not percolated down to the deeper aquifers yet, 3.) There are intervening (!� clay soil strata below, attenuating downward nitrate movement, and/or 4.) There is significant l denitrification potential within the underlying soil and aquifers, especially at the deeper depths. (§ 7.0) CONCLUSIONS The perc test results for proposed Parcels 1, 2 and 3 show acceptable percolation for the management of anticipated septic system effluent flows at the deeper depths representative of seepage pits. For Parcel 2 exclusively, effluent management may occur from leachlines, as well as seepage pits. As noted from the perc test results, as the soil becomes saturated,percolative potential decreases. The underlying soils possess increasing moisture content with increasing depth. This is due to the irrigation of the tomatoes which were harvested approximately three weeks prior to drilling. High moisture content soils are beneficial for the suppression of nitrification, and the promotion of denitrification of nitrate molecules that may have formed. The deep percolation tests revealed an anomaly on proposed Parcel 1. No percolation existed within the test boring for the first two and one-half hours. Then perc rates began with acceptable percolation. At the end of four hours, the water drop was 0.96" which is 0.04" below a passing rate. These unusual rates may be attributable to soil saturation phenomena occurring at perc test depth. Irrigation water obviously congregated in the area of testing since the water flowed from south to north to irrigate the tomatoes. This water then percolated downward to create saturated soil conditions. It is theorized that due to some unknown phenomenon, percolation started after the observed length of time, even though there was no standing water after 24 hr pre-saturation. As referenced on Page 2, due to this unusual phenomenon, EHD requirements will be to double the number of calculated seepage pits for any future residential development on Parcel 1. It is our recommendation that if residential development occurs on Parcels 2 and 3, this same procedure of doubling the number of required seepage pits be considered,particularly if row crop production will remain in the surrounding acreage. EHD requires that there be sufficient distance for"treatment"of septic effluent before it encounters the groundwater table. This distance is normally regarded to be ten feet. Therefore, sufficient distance exists between the bottom of a maximum depth seepage pit at 25 feet and the current groundwater depth of approximately 95 feet. (§ 6.8) The number of leachlines and septic tank size is unknown for any future residential structure ( Q� since the number of bedrooms is unknown at this time. Page -5- Chesney Consulting