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7Thecent Linesof Equal Depth map (Spring 2018) indicates the groundwater depth to be <br /> ely 25 feet. Historical groundwater data indicates the water table may have been as <br /> shallow as 15 ft bgs. <br /> The 2018 Lines of Equal Elevation Map illustrates the groundwater directional flow to be generally <br /> in a northwesterly direction. Groundwater flow in this locale can be variable due to several <br /> influences such as surrounding irrigation. <br /> SSS§2.1,4.2. Since the surrounding properties have also been intensely farmed for several <br /> decades, the probability for nitrate contamination in the underlying soil and groundwater is <br /> significant. However,the on-site well water reveals a comparatively low nitrate concentration of <br /> 6.48 mg/L, as nitrate-nitrogen(MCL=10 ppm). <br /> NLS§2.2,3.1, SSS§4.2. As referenced,the project has an on-site water well for staff and <br /> employees. The well is undergoing classification as a public well due to the number of employees. <br /> The following Table summarizes the test results. <br /> TABLE 3 <br /> TEST RESULTS FOR THE ON-SITE DOMESTIC WELL <br /> ANALYTE ON-SITE DOMESTIC WELL <br /> Nitrate(As nitrate-nitrogen) 6.48 mg/L <br /> DBCP ND <br /> Dibromochloropropane (Non Detect) <br /> Alkalinity 184 mg/L <br /> Calculation of Alkalinity Requirement for Nitrification <br /> The nitrate-nitrogen loading calculations below are contingent upon the environmental factors <br /> required for nitrification to occur. These conditions include soil pore-space oxygen content, soil <br /> temperature,pH, electrical conductivity, organic matter, cation exchange capacity, and alkalinity. <br /> Alkalinity in wastewater effluent is derived from the well water supply in addition to the <br /> introduction of human wastes. Nitrification consumes approximately 7.1 mg of alkalinity for every <br /> mg of ammonia-nitrogen(NH4-N) oxidized. Nitrification of the average Total Nitrogen(TN) <br /> concentration of 62 mg/L, as determined on Page 6 would require: 62 mg/L NH4-N x 7.1 mg <br /> CaCO3 =440 mg/L alkalinity. The alkalinity in the domestic well water supply was measured at <br /> 184 mg/L. The alkalinity of the wastes is unknown, but the combination of the well water and <br /> wastes would most likely be below 440 mg/L which would thus inhibit nitrification to an <br /> indeterminable extent. <br /> 4 <br /> Chesney Consulting <br />