Laserfiche WebLink
TABLE 3 <br />PRECIPITATION AND ETo DATA FOR MANTECA CIMIS STATION #70 <br />Month <br />Monthly Precipitation <br />(Avg. 2015-2019) <br />ETo Average <br />(Avg. 2015-2019) <br />Potential Deep Percolation <br />(in/mo) <br />(in/mo) <br />(in/day) <br />January <br />2.65 <br />1.12 <br />0.04 <br />1.53 <br />February <br />1.12 <br />2.11 <br />0.08 <br />-- <br />March <br />1.79 <br />3.5 5 <br />0.12 <br />-- <br />April <br />1.43 <br />4.28 <br />0.14 <br />May <br />0.49 <br />6.67 <br />0.22 <br />-- <br />June <br />0.18 <br />7.87 <br />0.26 <br />-- <br />July <br />0.00 <br />8.26 <br />0 27 <br />-- <br />August <br />0.01 <br />7.12 <br />0.23 <br />-- <br />September <br />0.06 <br />5.23 <br />0.17 <br />-- <br />October <br />0.56 <br />3.67 <br />0.12 <br />-- <br />November <br />1.44 <br />1.88 <br />0.06 <br />-- <br />December <br />1.95 <br />1.28 <br />0.06 <br />0.67 <br />TOTALS (in.) <br />1 11.68 <br />53.0 <br />------ <br />2.21 <br />This data illustrates a relatively high potential for there to be significant evapotranspiration from the <br />wastewater disposal system design that takes advantage of evapotranspiration during the favorable months <br />of March through October. <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, wastewater flow volumes must be determined as <br />accurately as possible. Domestic flow volume projections are typically approximated from the USEPA <br />Onsite Wastewater Treatment Systems Manual, Pg. 3-4. However, the EHD now specifies residential <br />(domestic) flow volumes to be assigned 100 gallons for the first bedroom and 50 gallons for each additional <br />bedroom. The following calculations summarize the wastewater flow volumes projected for the subject <br />property: <br />Ms. Vierra's existing house has one bedroom: 100 gals/day <br />Her son's house has three bedrooms: 100 + 50 + 50 = 200 gals/day <br />Ms. Vierra's proposed house will also have three bedrooms and a toilet/sink in the pool cabana (counted as <br />one bedroom): 100 + 50 + 50 = 50 = 250 gals/day <br />Total wastewater flow volumes from the subject Parcel = 550 gals/day. <br />Page -4- <br />Chesney Consulting <br />