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concentrations due to properties being orchards and rural residential. The existing site contains a nitrate loading concentration of only 4.38 mg/L-N, confirming the site does have capacity for the proposed improvements. 5.2 Description of impact of rainfall contribution of nitrate load to the project site: The impact of rainfall contribution on the project site was completed to determine the nitrate load. The average monthly precipitation and evotranspiration are required to calculate the site nitrate load. These two values are used to estimate the deep percolation. The deep percolation is estimated by analyzing the difference between the monthly average precipitation and the evotranspiration,when the evotranspiration exceeds the monthly average precipitation. These calculations are attached in the Appendix. The data for the potential evotranspiration water was obtained from the California Irrigation Management Information System (CIMIS). The project is located within an area designated as Zone 12. Based on the values for this area along with the average monthly precipitation values obtained from the Western regional Climate Center (Station 242) an estimate of the deep percolation of rain for the project was determined. The results for the deep percolation at the site were 9.98 in./year. The nitrate concentration is estimated to be about 1 mg/L-N. (Hantzsche and Finnemore, 1992). 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 sources of nitrates are the existing septic systems in use by an existing parcel for a modular office and a welding shop. The existing septic systems were accounted for when determining the approximate nitrate concentration, the site is expected to produce minor increase of nitrates with the proposed development. 5.4 Discussion of all proposed future on-site sources of nitrate to soil and groundwater and the contribution of nitrate load from these sources to the project site: The future use of the site will remain consistent. It will continue to be used as an orchard, a welding shop and storage for farming equipment associated with the owners tree trimming business. The improvements are proposing an expansion to the existing building used for storage of farming equipment. The expansion has an insignificant impact to the septic system. The modular office is being relocated and would continue to have the same effluent volume that is currently being produced since only two employees use this bathroom. Two employees use the existing welding shop. Both the modular office and welding shop have one toilet and one sink. The maximum number of employees using the modular office and welding shop is two per day. The shop would produce an average of 15 gallons/day per person of effluent. The modular office would produce an average of 30 gallons/day per person of effluent. In calculating the effluent levels for the site,we calculated 2 people would use the welding shop, 2 people would work in the modular office, 3 weekly delivery drivers. A safety factor of 2 was accounted for. Therefore, the approximate values could be doubled, without surpassing the allowed nitrate loading concentrations. This method of determining nitrate loads is conservative on its own, as the value of gallons per day was used in the calculations was 360 gal/day and did not exceed 10 mg/L-N. This method of calculating the nitrate loading concentration is conservative as it does not include lateral dispersion or mixing of groundwater. These factors of safety are additional to 3