Laserfiche WebLink
July 21,2003 <br /> Job Number:LG03-120 <br /> Page 10 <br /> 7.3 Quantity and Quality of Deep Percolating Rain Water <br /> An estimate of the quantity and quality of rainfall was required for the analysis. The weather <br /> station information for Stockton's precipitation and evaporation was used to estimate the deep <br /> percolation of rain for the site located in Ripon. The deep percolation of rain was estimated to be <br /> 5.01 inches. Please refer to Plate 1 for details regarding the deep percolation of rain. The nitrate <br /> concentration of rain fall was estimated to be 1 mg/L-N.' <br /> 7.4 Denitrification Estimate <br /> Denitrification is an important process which occurs within the leach field whereby certain <br /> bacteria utilize the oxygen in the nitrate(NO ) and release nitrogen gas (N2) to the atmosphere. <br /> Denitrification is expressed as a percentage, and the normally accepted range is 10 percent to 35 <br /> percent. Soils with higher clay content, moist soil conditions, high pH, and organic material <br /> denitrify by about 35 percent and soils with high sand content and fast percolation rates are <br /> estimated to denitrify at a lower rate, about 10 percent to 15 percent. Due to the sandy soils which <br /> exist on the site, the denitrification factor is estimated to be about 10 percent. <br /> 7.5 Nitrate Loading Scenarios '--- <br /> Two nitrate loading scenarios were performed to determine the impact for both the large <br /> designated remainder parcel of 79.8 acres and the smaller 2.0-acre parcels. For each scenario, the <br /> previously described assumptions were unitized in the Hantzshe and Finnemore equation. The <br /> likely added contribution from future agriculture was not considered however it is expected to <br /> also contribute to some degree. <br /> 9 Hantzshe N.N.,Finnemore,E.J. 1991,Predicating Ground-Water Nitrate-Nitrogen Impacts. Ground <br /> Water,Vol. 30,No.4. <br /> nEll <br />