SR0080658 - Laserfiche WebLink

Home Browse Search

5.3 Description of all current on-site sources of nitrate to soil and groundwater and the contribution of nitrate load from these sources to the project site: The only source of nitrates is the existing septic system in use by an existing parcel for residential uses and agriculture use. The existing septic system was accounted for when e g roximae m ate concentration,the site could expect with the proposed development. Y6"S7 5.4 Discussion of all proposed fu :reon-site sources of nitrate to soil and groundwater and the contribution of nitrate load roese sources to the project site: The future use of the site will be a warehouse with tw batms. For a rural service commercial use,the approximate flow rate that is expected to be use is between 2000 gallons per day per acre per County Standards. The site being used is approximately 15,9 square1eet or OT. 6 acres of Mldffig_area. The San Joaquin County Environmental Health Department requires that a safe ctor of 2 be used. Therefore,the approximate values used should be doubled. As this method of determining nitrate b loads is conservative on its own, the value of 2928 gallons per day was used. This method is conservative as it does not include lateral dispersion or mixing o groundwater. These factors of safety are additional to the County's factor of safety. The site is expected to grow in phases, but the addition of this first phase has no impact on the 45 acre site. �\ �00P ;1 The average total nitrogen concentration of domestic waste water is about 20-85 mg/L-N, although 35-45 mg/L-N ' oximation(Crites and Tchnobanglous). The value selected for this site 45 mg/L-N ass g this site shall experience a larger concentration. w The site will experience a process of denitrification as the soil naturally treats surface material through natural forms. Denitrification is a process that occurs when bacteria uses oxygen in the nitrate (NO3) and release nitrogen(Nz)into the atmosphere. Denitrification can be variable to the type of soils,chemical properties,moisture content and other variables. Based on the sandy loams on site and the high percolation rates,this site's soil has low levels of denitrification. It is expected that a site with soil of these characters a approximately about 10-15% of denitrification. The value used for this sit was 15%. j� 5.5 Calculate mass balance of nitrogen loading considering all potential sources identified v using Hanztch/Finnemore equation: Using the data mentioned within this report and the attached Soil Suitability Report the mass balance of nitrogen loading for this site was calculated, this was done using Hanztch/Finnemore formula. B on e- ch/Fimemore equation this 45.11 acre site would contain a Nitrate Load (N of 4.15 mg/L-N. e site can handle up to 10,000 gallons per day, a flow much more significant an the proposed 2,928 gallons. It would require more than 10,000 gallons per day to surpass the maximum level (MCL) of 10.0 mg/L-N in drinking water. 6.0 Discussion of nitrate loading results relative to proposed method of wastewater disposal 6.1 Discussion of total nitrate impact from proposed project: There are possibilities that the percolating effluent could affect water conditions. The Hanztch/Finnemore equation added to the County's factor of safety of two dl*rm'm*-sh those risks, but no major additions should be made beyond the proposed improvements me oned previously without an update to this report. 5 e