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Frise in the water table elevation may be attributed to the cropland surrounding the the south and west. Irrigation recharge can have a significant influence on the and surrounding water table. The critical issue regarding the groundwater elevation is: ust be sufficient distance between the soil/effluent interface and the highest anticipated undwater for sufficient treatment of effluent to occur. This is generally accepted to be five feet, and 2.)The water table cannot encroach upon the septic tanks, which may cause buoyancy. On November 30, 2007, the referenced well within the subject area was sounded and the standing water level measured at 14.8 ft. The well casing is approximately one foot above surrounding grade, thus making the standing water level 13.8 ft below grade. This is approximately the same measurement determined from the deep boring conducted for the Preston project. NLS§ 2.2, 3.1, SSS§ 4.2. As referenced, EHD is requiring that no water chemistry be conducted on the on-site well,the Preston well that serves the entire 34 acres, or on the water table. Calculation of Alkalinity Requirement for Nitrification The nitrate-nitrogen loading calculations on Page 8 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 82 mg/L, as determined on Page 8 would require: 82 mg/L NHa N x 7.1 mg CaCO3 =582 mg/L alkalinity. The alkalinity in the domestic well water supply was tested for the Preston project, and found to be 110 mg/L. Consequently, nitrification may be inhibited to an indeterminable degree. E. SURFACE WATER INFORMATION Storm water management consists of an existing on-site retention basin. Percolating stormwater may produce dilution effects to the underlying water table. Groundwater dilution effects can only be truly discerned with 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,or a water source including effluent water recharge. Climatic Data: Rainfall versus Evapotranspiration NLS§3.2. 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, which is the closest data 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): 5 Chesney Consulting