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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 of the underlying aquifers supplying the domestic water supply is approximately 150 ppm based on tests of surrounding domestic wells. This alkalinity concentration may theoretically retard nitrification to an indeterminable degree. Mounding Analysis /, Since the groundwater was measured(athe 2 fee)from the sounding of an adjacent domestic well, adverse mounding potential should bn stent and inconsequential. Additionally, since a large percentage of sand is known to occur deeper depths, this would also, in all likelihood, prevent the formation of the mound phenomenon under the disposal area. A distance of approximately 20 feet between the soil/effluent interface and the top of the underlying water table should be maintained. For wastewater treatment(destruction of bacteria and viruses) to occur, the distance effluent should/travel under unsaturated conditions through the soil environment is generally regarded to b� 5 feet. E. SURFACE WATER INFORMATION Storm water management is proposed to be by on-site management. There should be no impact to percolating effluent water from the septic system. Since the groundwater directional flow is north- northwest,percolating rainwater from runoff from the Produce Stand building into the top aquifer mixing layer may create a dilution effect to the downgradient percolating septic system effluent. Groundwater dilution effects can only be truly discerned with complicated 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, or by percolating rainwater recharge. Climatic Data: Rainfall versus Evapotranspiration .NLS§3.2 It is generally and scientifically accepted that when precipitation exceeds evapotrans- p' tion(�to), 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 chart illustrates rainfall and evapotranspiration for the Stockton area, which is the closest data to Manteca available. 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): 7 Chesney Consulting