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27 April 2020 AdvancedGeo <br /> Project No. 20-5084 A-Employee Owned Company <br /> Page 14 of 15 <br /> 9.7. IMPACT OF NITROGEN LOADING FROM SITE PROJECT TO <br /> DOWNGRADIENT WATER SOURCES <br /> The recharging of groundwater is the most likely potential feature that could impact future <br /> nitrogen loading. Since the subject property is flat, AGI does not anticipate percolating <br /> effluent will affect any nearby water sources. Based on the volume of wastewater to be <br /> generated, the potential vertical migration would not likely degrade the local groundwater. <br /> A total of 10.0 ppm of additional nitrogen is estimated to be added to the site over the <br /> long term through wastewater recharge from the existing and proposed septic systems. <br /> The nitrogen loading value is equal to the desired value of 10 ppm. <br /> 10.0. TOTAL NITRATE IMPACT FROM PROPOSED PROJECT <br /> Based on the method and assumptions described, proposed NO3_N mass of wastewater <br /> and the calculations of the NO3_N loading predicted, the proposed development should <br /> not negatively impact NO3_N loading rates within the aquifer. The soil at the site appear <br /> to be adequate for nitrate degradation and proper leaching of wastewater. A total of <br /> 10.0 ppm of additional nitrogen is estimated to be added to the site over the long term <br /> through wastewater recharge from the existing and proposed septic systems. <br /> 11.0. MITIGATION METHODS PROPOSED <br /> To mitigate any known or potential future impacts to soil and groundwater of nitrate from <br /> the existing and proposed septic systems, the following mitigations could be <br /> implemented: <br /> • Maximize wastewater hold time where practical (retention). <br /> • Avoid use of bioattenuation chemicals (bleach etc.). <br /> • Properly and regularly maintain property septic systems. <br /> • Use EHD criteria for sizing the septic disposal field. <br /> If re-location or expansion of leach fields becomes necessary, leach lines should include <br /> high organic substrates under and surrounding the lines installed. <br /> 12.0. CONCLUSIONS AND RECOMMENDATIONS <br /> Based on this Soil Suitability and Nitrate Loading Study, AGI concludes the following: <br />