SR0079728 - Laserfiche WebLink

Home Browse Search

r Nitrate Loading Study Flag City#4 ■ Lodi, California Irerracon September 20, 2018 ■Terracon Project No. NA187043 structures associated with the adjoining properties are connected to individual septic systems. Therefore, off-site sources of nitrate include septic systems, agricultural land use, and natural processes. 3.2 Contribution of Rainfall An estimate of the quantity and quality of rainfall was required for the nitrate loading analysis. The estimate of deep percolation of rain is based on the average monthly precipitation of rain fall and evapotranspiration for Lodi, California. The estimate first determines whether the average monthly precipitation exceeds average monthly potential evapotranspiration. If so, then the difference is potential deep percolation. This method does not consider runoff, although due to the relatively flat nature of the site, runoff should be minimal. Average precipitation and potential evapotranspiration were obtained from the California Irrigation Management Information System (CIMIS) website. Refer to Appendix B for the data and calculation. Table 2. Estimate of Deep Percolation of Rain for the Site Location Deep Percolation of Rain Lodi 5.76 inches per year Based on this method, the average deep percolation of rain for the Lodi area is estimated to be 5.76 inches/year. The nitrate concentration of rainfall is estimated to be 1 mg/L-N (Hantzsche and Finnemore, 1992). 3.3 Current On-Site Sources of Nitrate The site is currently fallow agricultural land; therefore, the current on-site sources of nitrate includes the existing agricultural land use and natural processes. 3.4 Future On-Site Sources of Nitrate The site is proposed to be developed with a truck terminal and heavy equipment storage yard which will include a 400 SF office with restroom and septic system. Therefore, the future on-site sources of nitrate will include the proposed septic system and natural processes. 3.5 Quantity and Quality of Wastewater from Project The following discussion is for determining the long-term wastewater flow generated from the proposed development for the nitrate loading analysis and should not be used for septic system design purposes. Typically, use estimates for the sizing of septic systems include a peak use factor, whereas the numbers discussed here are based on long-term averages. We understand that the project will consist of a trucking terminal and will be open 10 hours per day six to seven days per week year round. There will be up to 20 permanent employees working 10 hour shifts Responsive■ Resourceful s Reliable 6