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• NITRATE LOADING STUDY <br /> The method utilized for the nitrate loading analysis is based on a simple and convenient <br /> mass balance formula, discussed in a published article by Hantzsche and Finnemore <br /> (1992). <br /> Hantzsche and Finnemore have found from investigations conducted in the Chico, <br /> California area, the water quality in the upper saturated ground-water zone closely <br /> approximates the quality of percolating effluent from septic systems. They have <br /> developed a simple method that could be used to estimate the quality of the percolating <br /> effluent from septic systems. The quality of the percolating effluent may represent the <br /> potential worst-case condition the upper aquifer would ever experience from the use of <br /> on-site septic systems. Mixing and dilution in the aquifer as well as adsorption and <br /> adhesion in the soil substantially reduce the concentration of percolating effluent. <br /> The Hantzsche and Finnemore equation is a conservative approximation of ground- <br /> water nitrate-nitrogen concentration resulting from the combined effect of on-site <br /> sewage disposal systems and precipitation of rain. The equation and method are for <br /> estimation of long-term effect ground-water quality, and are not intended for prediction <br /> of seasonal changes (Hantzsche and Finnemore, 1992). <br /> The method takes into account the development area, soil denitrification factor, rainfall <br /> • recharge rate, rainfall nitrate concentration, waste effluent quantity, and waste effluent <br /> nitrate concentration from on-site septic systems. <br /> On-Site Sources of Nitrate <br /> There are no current on-site sources of nitrate. The future on-site source of nitrate will <br /> be the new septic system for the proposed house. <br /> No contribution from any irrigation or soil amendment is considered for the <br /> Hantzsche/Finnemore method. It is reasonably assumed that any irrigation or soil <br /> amendments would be applied at close to agronomic rates for a net balance of plant <br /> irrigation and nutrients. <br /> Contribution of Rainfall <br /> An estimate of the quantity and quality of rainfall was required for the nitrate loading <br /> analysis. The Hantzsche and Finnemore method utilizes the "average recharge rate of <br /> rainfall' in calculating potential nitrate impacts to the aquifer. Not all rainfall will <br /> percolate into the aquifer; evapotranspiration, the sum of evaporation and plant <br /> transpiration, will reduce percolating effluent, especially in summer months. <br /> • LOGE 1802 Page 5 <br />