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CONCLUSIONS <br /> Based on the method and assumptions described, the result of the nitrate loading <br /> estimate indicates that the proposed development on the Site has the potential to cause <br /> a buildup of nitrates in the aquifer of 14.3 mg/L-N, above the MCL of 10 mg/L-N. <br /> The depth of ground water based on recent aquifer levels is estimated to be 95 to 100 <br /> feet below ground surface. The ground-water flow is to the east or east-southeast at a <br /> rate of approximately eight to 15 feet per mile in the vicinity of the Site. <br /> One well is located on the Site, but it is not currently operational. No water sample was <br /> collected as part of this study. Samples from one nearby well have been found to <br /> contain DBCP, according to San Joaquin County Environmental Health Department <br /> records. <br /> Because of the result of the nitrate loading calculation, the San Joaquin County <br /> Environmental Health Department will require annual monitoring of the domestic well for <br /> nitrate. The purpose of this monitoring is to determine whether nitrate levels in the <br /> ground water are increasing. <br /> No other nitrate mitigation measures are being required by the San Joaquin County <br /> Environmental Health Department at this time. However, since the construction of a <br /> new septic system is planned, the owner has the opportunity to modify the septic <br /> system to reduce nitrate levels in the effluent. Simple septic system modifications that <br /> have been employed for other projects in San Joaquin County include installing <br /> oversized septic tanks and adding additional carbon, such as wood chips, to the leach <br /> lines. The San Joaquin County Environmental Health Department has indicated that <br /> these modifications promote additional nitrogen reduction which may result in a <br /> lessened impact to the aquifer. Additionally, the costs of these modifications are <br /> minimal compared to the potential long-term benefit. If modifications to the system are <br /> desired, the septic contractor should contact the San Joaquin County Environmental <br /> Health Department for direction. <br /> LOGE 1832 Page 9 <br />