SU0006112 SSNL - Laserfiche WebLink

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Fbe rillers' Logs for nearby domestic wells were not found in the microfiche files at EHD. ore, the underground lithology specific to the subject property could not be discerned. It is derstanding the property is not subject to 100-year flooding,but this final determination will e by John Shoup, PLS. Surface water runoff is diverted into the surrounding vineyard. 4.3 and 4.5) As referenced,there are two wells on the subject property. The first well sampled was the domestic well directly east of the house. This well was allowed to pump water for 15 minutes to ensure the sampling of aquifer formation water. The sample was taken from the hose bibb at the pump house. This sample was analyzed for nitrate (as nitrate) and the agrichemical DBCP. The second well sampled was the irrigation well that irrigates the vineyard. This sample was taken from the sample port on the north side of the outlet pipe. This well had been pumping to irrigate the vineyard on an exceptionally hot day; therefore, sampling of aquifer formation water was ensured. Following EHD requests, this well was only tested for nitrate. -'�(§4.6) A clear plastic bottle was used for both nitrate samples and three amber VOC bottles with preservative were used for the DBCP samples. The samples were placed in a cooled ice chest and transported under the attached Chain of Custody to FGL Labs in Stockton, California to be analyzed for nitrate, and Dibromochloropropane (DBCP). -*"�Ifl§4.2 and 4.4) Well water analysis reveals a very low nitrate(as nitrate-NOD concentration of 5.2 ppm for the domestic well, and a very low concentration of 2.8 ppm nitrate for the irrigation well. DBCP were found to be Non-Detect (ND). The Maximum Contaminant Level (MCL) for nitrate in drinking water is 45 ppm. These very low nitrate concentrations found in both wells may be attributed to: 1.)Potential nitrate concentrations have not percolated down to the deeper aquifers yet, 2.) There may be intervening clay soil strata below, attenuating downward nitrate movement, or 3.)There is significant denitrification potential within the underlying aquifers, especially at the shallower aquifer depths. (§ 7.0) CONCLUSIONS the perc test results for proposed Parcel 1 show acceptable percolation for the management of existing and any future septic system effluent flows. Effluent management will occur at the typical leachline trench depth of 42 inches, at a sump depth of 12.5 ft, and at a seepage pit depth of 25 ft. This also applies to any structure that may be built on the Designated Remainder. As noted from the perc test results, as the soil becomes saturated, percolation potential decreases. �At the discretion of EHD, any future septic system will be installed with either sumps or seepage pits. Since this locale is denoted as a"seepage pit" area, it is most likely that seepage pits will be installed. Although the permeability is greater at the 12.5 ft depth versus the 25 ft depth, as biomat formation"climbs"up the walls of the seepage pits, it will eventually encounter this higher porosity soil for greater effluent management. ' Any future proposal to build on Parcel 1 or the Designated Remainder Parcel will require a perc test Lnheic location where the system is to be installed. Potential homebuilders on these Parcels e aware that any futureleachfield must be installed within 100 feet of the perc test Pa e -4- Chesney Consulting