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1� 2. .3 Surrounding irrigation of row crop and pasture acreage does influence water-table. NLS.§ g . g p depth, as w�1as quality with respect to nitrate-nitrogen.`There is no question that irrigation of the corn to the south of the project site has influenced the water table depth by raising it 2 feet higher in comparison to the downgradient water table measurement. However, this will only be a "seasonal"phenomenon during irrigation season. /CALCULATION OF ALKALINITY REQUIREMENT FOR NITRIFICATION The nitrate-nitrogen loading calculations below 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, alkalinity, et al. Alkalinity in wastewater'effluent is derived from the domestic water supply in addition to the introduction of wastes:'.Nitrification consumes proximately 7.1 mg of alkalinity for eve mg of ammonia-ni�rtrngen �- oxidized. Nitrification of the average Total Nitrogen(TN) concentration of 66 mg/L(not including septic tank and biomat nitrogen concentration decreases), a5-determined below on Page 10 woul require: 66 m ,N x 7.1 mg CaCO =469 mg/L alkalinit . The alkalinity in t e domestic water supply, the introduction of domestic wastes, and the current water table alkalinity of approximately 334 mg/L (avg.) may be deficient, or marginal. Therefore, nitrification may be inhibited. i TABLE 3 SSM 4.4 ;W..... l' Si'g - ...a: NDERLYINGGROC7NDWATER'`ANALYSIS , ;> , WATER TABLE ANALYSIS UPGRADIENT TO WATER TABLE ANALYSIS DOWNGRADIENT TO THE SUBJECT PROPERTY THE SUBJECT PROPERTY ANALYTE LEVEL FOUND ANALYTE L FOUND Nitrate-As Nitrate 57 mg/L Nitrate-As Nitrate 69 mg/L M.C.L.=45 mg/L. M.C.L.=45 mg/L Total Dissolved Solids 1130 mg/L Total Dissolved Solids 151 D m PH_ 7.5 pH' 7.4 Total Alkalinity 286 mg/L Total Alkalinity 383 mg/L Chloride, Sodium 168 m 202 L Chloride, Sodium 168 mg/L,234�m�:J MOUNDING ANALYSIS l tReference.is made to the encountered groundwater table at an average of 8.5 feet below existing grade. This shallow,groundwater table may induce a phenomenon known as the mounding effect. A procedure developed by Finnemore and Hantzsche (1983) is used below to predict the long-term maximum rise of the mound: R - h=~H+Zn-2 where: 'h=distance from boundary to mid-point of the long-term mound, in ft H=height of stable groundwatertable above impermeable boundary, in ft Z.=long-term maximum rise of the mound, in ft Substituting known and.estimated values for the variables;we find the following. Page -7- Chesney Consulting