SR0079948 SSNL - Laserfiche WebLink

Home Browse Search

CONCLUSIONS Based on the method and assumptions described, the result of the nitrate loading estimate indicates that the existing and proposed development on the Site has the potential to cause a buildup of nitrates in the aquifer above 10 mg/L-N. A water sample was collected from the domestic water well; nitrate was detected at a concentration of 8.5 mg/L-N in the sample, slightly below the MCL of 10 mg/L-N. The depth of ground water based on recent aquifer levels is estimated to be 99 to 125 feet below ground surface. The ground-water flow direction is uncertain in one map consulted; for the other map, the flow is to the northeast at a rate of approximately 20 feet per mile. Because of the result of the nitrate loading calculation, the San Joaquin County Environmental Health Department will require annual monitoring of the domestic well for nitrate. The purpose of this monitoring is to determine whether nitrate levels in the ground water are increasing. No other nitrate mitigation measures are being required by the San Joaquin County Environmental Health Department at this time. However, since the construction of a new septic system is planned, the owner has the opportunity to modify the septic system to reduce nitrate levels in the effluent. Simple septic system modifications that have been employed for other projects in San Joaquin County include installing oversized septic tanks and adding additional carbon, such as wood chips, to the leach lines. The San Joaquin County Environmental Health Department has indicated that these modifications promote additional nitrogen reduction which may result in a lessened impact to the aquifer. Additionally, the costs of these modifications are minimal compared to the potential long-term benefit. If modifications to the system are desired, the septic contractor should contact the San Joaquin County Environmental Health Department for direction. LOGE 1840 Page 10