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L ..,i 7po�rtential rise in the water table elevation may be from the cropland surrounding the property to the south. Irrigation recharge can have a significant influence on the underlying and surrounding watetable, although in this locale it is my opinion that the rise in the water table elevation would be minimal due to the sandy nature of the underlying soil at the water table depth. The critical issue regarding the groundwater elevation is: 1.)There must be sufficient distance between the soil/effluent interface and the highest anticipated depth to groundwater for sufficient treatment of effluent to occur, which is generally accepted to be five feet, and 2.) The water table cannot encroach upon the septic tanks, which may cause buoyancy. These two issues are inconsequential to this project. NL § 2.3 SSS 4.3,4.4,4.5 As referenced, there is an existing well on the property that will serve the ew d m ' However, before the well could be sampled for this Study, the pump, pressure tank,piping and wiring were all stolen leaving only an open casing. Subsequently, it was decided to purge the well with compressed air as if it were being developed. On November 13, 2006, this procedure was done which brought large volumes of rusty, sandy water to the surface. This may be beneficial for the future operation of the well. After several well casing volumes were purged, the well water was sampled from the water column �= rising up from the casing. A clean glass bottle was used to capture sample water, ch was then transferred into the respective test containers, as noted on the Chain of Custody. These sample containers were placed in a cooled ice chest and then transported to FGL Environmental Laboratories in Stockton, under the attached Chain of Custody. The constituents tested were for nitrate, Dibromochloropropane (DBCP), Total Alkalinity and chloride. Medium- to-high groundwater chloride concentrations may indicate contamination from septic system effluent, since human wastes are generally high in chloride content. Chlorides travel exceptionally well in the soil environment, even better than nitrate, and can be an excellent indicator of 1 effluent pollution. The well water analysis reveals a very low concentration of chloride `t 2 pp which may indicate virtually no contamination of the underlying drinking water aquifers o septic system effluent. Calculation of Alkalinity Requirement for Nitrification The nitrate-nitrogen loading calculations on Page 12 are contingent upon the environmental factors required for nitrification to occur. These conditions include soil pore-space oxygen content, soil temperature,pH, electrical conductivity, organic matter, cation exchange capacity, and alkalinity. Alkalinity in wastewater effluent is derived from the domestic well water supply in addition to the introduction of wastes. Nitrification consumes approximately 7.1 mg of alkalinity for every mg of ammonia-nitrogen(NH4-N) oxidized. Nitrification of the average Total Nitrogen(TN) concentration of 113 mg/L, as determined on Page 11 would require: 113 mg/L NH4 N x 7.1 mg CaCO3 = 802 mg/L alkalinity. The alkalinity in the domestic water supply is presently 150 ppm, which may theoretically retard nitrification to an indeterminable degree. 6 JJ Chesney Consulting