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Fr�f/ Ag WE A LY I ANALYTE CONCENTRATION MAXIMUM CONTAMINANT LEVEL FOUND (MCL) Nitrate(As Nitrate) 5.4 ppm 45 ppm DBCP Non-Detect-ND 0.2 µ2 North Well Nitrate(As Nitrate) 27.5 ppm 45 ppm DBCP Non-Detect-ND 0.2 R2 South Well Nitrate(As Nitrate) 46 ppm 45 ppm DBCP Non-Detect-ND 0.2 t" (§ 7.0) CONCLUSIONS The perc test results for proposed Parcel 1 show acceptable percolation for the management of anticipated septic system effluent flows. Effluent management from the new residential structure will occur at the typical leachline trench depth of 42 inches that will extend into the surrounding vineyard, as referenced. As noted from the perc test results, as the soil becomes saturated, the percolation potential does not decrease substantially, which is regularly observed. The underlying soils appeared to possess slightly decreasing moisture content with increasing depth. This may be due to the low rainfall totals that have occurred this past winter. High moisture content soils are beneficial for the suppression of nitrification, and the promotion of denitrification of nitrate molecules that may have formed through nitrification in the upper soil environments. 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 five feet. Therefore, sufficient distance exists between the bottom of a maximum depth leachline trench at 42 inches and the current groundwater depth of greater than 13 feet (156 inches), as evidenced by the backhoe test pit (156 inches minus 42 inches= 114 inches =9.5 feet). 4§ 6.8) The number of leachlines and septic tank size will be dependent upon the number of LLdesignated ooms within the new house. Leachline length in this locale is stipulated by EHD to be 100 feet ach bedroom. Determination of a bedroom is made by closets. If a room has a closet, it is as a bedroom. 'n No problems are anticipated for any future septic system on the Parcel, other than typical pan concerns. An engineered septic system will not have to be installed for this proposed minor ivision unless there are continual failures. The new system must have at least a 50% standby cement area incorporated into the design, which will be easily achieved due to the surrounding yard. Page -5- Chesney Consulting