Laserfiche WebLink
• Rainfall recharge (deep percolation of rain) is a significant factor in the nitrate loading <br /> estimate; however, data on rainfall recharge rates are not widely available. For the <br /> Chico area, Hantzsche and Finnemore present an average rainfall of 22.5 inches per <br /> year and an estimated rainfall recharge of 16.8 inches per year; the recharge rate is <br /> calculated to be 75 percent of the average rainfall. Because the Chico area is similar <br /> geologically to San Joaquin County, for the purpose of this report Live Oak has selected <br /> 75 percent of rainfall to represent the estimated rainfall recharge for the project area. <br /> Rainfall data for the Tracy area was obtained from the Western Regional Climate <br /> Center. The Tracy Carbona station (048999), the closest active station to the Site, <br /> reports the average total annual precipitation from March 1906 through May 2016 to be <br /> 9.86 inches. By assuming 75 percent of this precipitation percolates to the aquifer, the <br /> value of 7.4 inches average recharge of rainfall is obtained. <br /> The nitrate concentration of rainfall was estimated to be 1 mg/L-N (Hantzsche and <br /> Finnemore). <br /> Quantity and Quality of Domestic Wastewater <br /> Mr. Atwal proposes to place three new employee housing units on the Site; two of these <br /> will have three bedrooms, while the third will have two bedrooms. A rental house and <br /> two existing employee housing units are located on the Site; Mr. Atwal stated that each <br /> existing residence has two bedrooms. <br /> • Crites and Tchobanoglous (1998) list a typical flow rate of 50 to 70 gallons per person <br /> per day for an individual residence. The San Joaquin County Enviromental Health <br /> Department has indicated that maximum flow and double occupancy within each <br /> bedroom should be considered for the nitrate loading assessment; as a result, a value <br /> of 140 gallons per bedroom per day has been selected (personal communication, <br /> January 6, 2017). <br /> The estimated flow values discussed here should not be used for the design and sizing <br /> of the septic system. The design and sizing of the septic system should utilize the San <br /> Joaquin County Environmental Health Department's On-Site Wastewater Treatment <br /> Systems Standards which incorporate peak and surge flow factors. The estimates used <br /> in the On-Site Wastewater Treatment Systems Standards may be greater than those <br /> discussed here. <br /> Based on 14 bedrooms total at 140 gallons per bedroom per day, the maximum <br /> average daily flow for the Site was estimated to be 1,960 gallons per day (gpd). A <br /> typical residential concentration of 35 mg/L of nitrate as N was selected (Crites and <br /> Tchobanoglous, 1998). <br /> • LOGE 1833 Page 6 <br />