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TABLE 3 WELL WATER ANALYSIS WELL ANALYTE CONCENTRATION MAXIMUM CONTAMINANT FOUND LEVEL(MCL) On-Site Nitrate Below Detectable Limits 45 ppm Domestic Well (As Nitrate) (BDL) Sampled from Hose Bibb to Dibromochloropropane Below Detectable Limits 0.2 µ/L(ppb) the south of DBCP (BDL) the well. Ethylenedibromide EDB Calculation of Alkalinity Requirement for Nitrification The nitrate-nitrogen loading calculations 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 on-site well water, in addition to the introduction of wastes in the effluent. 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 60 mg/L, as determined on Page 8,would require: 62 mg/L NH4-N x 7.1 mg CaCO3 =440 mg/L alkalinity. The alkalinity in the groundwater serving domestic water supplies in this locale are never this high due to the proximity of the referenced bodies of water. This low alkalinity concentration in the underlying groundwater supplies an insufficient and indeterminable amount of alkalinity for nitrification to readily proceed. E. SURFACE WATER INFORMATION Storm water management must be by on-site retention. Percolating rainwater over the total property acreage may theoretically provide a water table dilution effect to percolating wastewater effluent as accounted for in the nitrate loading calculations. Dilution effects can only be truly discerned with extensive groundwater monitoring and modeling. According to a scientific paper authored by Shaw and Turyk(1994), reduction of nitrate concentrations in groundwater can occur primarily through dispersion, by percolating rainwater, or a cleaner water source including effluent water recharge. Climati"ta: Rainfall versus Evapotranspiration NLS—),.Z It is generally and scientifically accepted that when precipitation exceeds evapotranspiration(Eto), deep percolation of surface rainwater may occur. Evapotranspiration refers to water evaporation that takes place both at the soil surface and transpiration by plants. The following Table illustrates rainfall and evapotranspiration for the Stockton area. Precipitation / data was obtained from the Soil Survey of San Joaquin County. The conservative "2 years in 10" data was used and not the "average rainfall"data. Evapotranspiration data was obtained from the California Irrigation Management Information System(CIMIS): 5