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FFa <br /> owing Table illustrates rainfall and evapotranspiration for the Tracy area. Precipitation <br /> obtained from the Soil Survey of San JogQuin County. The conservative "2 years in 10" <br /> s used and not the "average rainfall'data. Evapotranspiration data was obtained from the <br /> ia Irrigation Management Information System(CIMIS): <br /> TABLE, 3 <br /> PRECIPITATION AND Fin DATA FOR TRACY, CA <br /> Month 2 Years in 10 will have more Eto Average Potential Deep <br /> precipitation than: (in/mo) (in/mo) (in/day) Percolation(in/mo) <br /> January 2.93 1.55 0.05 1.38 <br /> February 2.21 2.24 0.08 <br /> March 2.38 3.72 0.12 <br /> April 1.51 5.10 0.17 <br /> May 0.71 6.82 0.22 <br /> June 2.09 7.80 0.26 <br /> July 0.28 8.68 0.28 <br /> August 1.05 7.75 0.25 <br /> September 0.84 5.70 0.19 <br /> October 1.06 4.03 0.13 <br /> November 2.10 2.10 0.07 -- <br /> 2.38 1.55 0.05 0.83 <br /> TOTALS(in.) 13.18 57.0 ------ 2.21 <br /> The Table illustrates that evapotranspiration far exceeds precipitation, even when using higher <br /> rainfall data that exceeds normal rainfall data by 56%. Only in the months of December and <br /> January would deep percolation potentially occur. This data illustrates a relatively high potential <br /> for there to be significant evapotranspiration(or bare soil surface evaporation) from a wastewater <br /> disposal system design that may take advantage of evapotranspiration during favorable months. <br /> NITRATE LOADING STUDY FINDINGS <br /> WASTEWATER FLOW VOLUME PROJECTIONS AND CHARACTERISTICS <br /> Wastewater Flow Volume Projections <br /> To determine nitrate-nitrogen loading from any project, as, flow volumes must be <br /> determined as accurately as possible. Domestic flow volume projections have been approximated <br /> from the USEPA Onsite Wastewater Treatment Systems Manual, Pg. 3-4. Residential (domestic) <br /> flow volumes average approximately 69 gallons/person/day. <br /> Page 4 of 12 <br /> Chesney Consulting <br />