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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) for the Staten Island region an estimate of the deep percolation of rain for the project was determined. The results for the deep percolation at the site were 17.01 in./year. The nitrate concentration is estimated to be about 1 mg/L-N. (Hantzche 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 residential uses and office/wine tasting facility. 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 be a winery. The improvements are proposing a new building that will be built in two phases. The building would only have four fixtures,three of them being sinks. The maximum number of employees using the building would be six employees during the harvest season. That number would go down to three during the remainder of the year. The existing site includes a house for which we expect to see 350 gal/day and an existing wine tasting facility that could provide capacity for the wastewater generated by 40 people/day. Based on the On-Site Wastewater Treatment Standards the winery would generate 20 gal/per/day. The proposed building improvements are capable of generating 15 gal/person/day of wastewater. Accounting for these existing and proposed improvements the site can sustain a flow of 1,240 gal/day. The is accounting for a factor of safety of two. 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 2,480 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 the County's factor of safety. The site is expected to grow in phases, but the additions to the existing site have no significant impact on the 4.38-acre site. 5