Laserfiche WebLink
10 May 2021 <br />Project No. 21-6390 <br />Page 13 of 14 <br />be added to the site over the long term through wastewater recharge from the proposed <br />septic system. The nitrogen loading value is below the desired value of 10 ppm. <br /> <br /> <br />10.0. TOTAL NITRATE IMPACT FROM PROPOSED PROJECT <br /> <br />Based on the proposed development, method and assumptions described, proposed <br />NO3_N mass of wastewater and the calculations of the NO3_N loading predicted, the <br />proposed development will not negatively impact NO3_N loading rates within the aquifer. <br />The septic system will be installed approximately 16 to 18 feet above ground surface in <br />fill material purposefully selected for the proper leaching of wastewater and nitrogen <br />degradation, and the native soil below surface grade in the project area appears to be <br />adequate for nitrate degradation and proper leaching of wastewater. A total of 7.96 ppm <br />of additional nitrogen is estimated to be added to the selected fill over the long term <br />through wastewater recharge from the proposed septic system. <br /> <br /> <br />11.0. MITIGATION METHODS PROPOSED <br /> <br />To mitigate any known or potential future impacts of nitrate to soil and groundwater from <br />the proposed septic system, the following mitigations could be implemented: <br /> <br /> Maximize wastewater hold time where practical (retention). <br /> Avoid use of bioattenuation chemicals (bleach etc.). <br /> Properly and regularly maintain the project septic system. <br /> Use EHD criteria for sizing the septic disposal field. <br /> <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 /> <br /> <br />12.0. CONCLUSIONS AND RECOMMENDATIONS <br /> <br />Based on this Soil Suitability and Nitrate Loading Study, AGI concludes the following: <br /> <br /> Presently, the percolation rate does not meet the minimum EHD standards in the <br />proposed septic system disposal field. Once the compacted soil in the septic <br />system disposal field has been removed and replaced with selected fill, a new <br />percolation soil suitability test should be performed to calculate the percolation <br />rate. <br /> The nitrogen loading rate is below the desired value of 10 ppm.