Laserfiche WebLink
Mr.Brian Rogers " <br /> December 2,2002 <br /> Page 3 <br /> Sewage Loading Equation: <br /> Q = 51(T)0.5 <br /> Where Q =loading rate(gal/day/ft). <br /> T=Percolation Rate(min/in). <br /> Assumptions: <br /> 1) Shallow percolation rate is 125-minutes per inch. <br /> 2) Three(3) feet of absorption area per linear foot of leach field trench. <br /> (6-inches each sidewall and 2-feet along the bottom width). <br /> 3) A two (2)bedroom SDU is proposed which can consists of three(3) persons <br /> utilizing approximately 70-gallons per day per person for 210-gallons <br /> average daily flow (70 gpd/person, Crites and Tchobanoglous, 1998,page <br /> 170, Table 4-1). <br /> 4) A factor of safety(FOS)of 1.5 or(150%)was utilized in the calculations for <br /> determining the minimum capacity of the system. The flow rate of 210- <br /> gpd was multiplied by the factor of safety resulting in a design flow of <br /> 315-gpd. <br /> The system calculations are presented on Sheet No. 1. Essentially,the proposed leach <br /> line sizes are based on approximately 315-gpd flow, a percolation rate of 125-min/in, and 3-feet' <br /> of absorption area per linear foot of shallow trench. The system will be sized for 100% of flow <br /> to shallow leach lines (0%flow to seepage pits). Essentially, the calculation indicates a total of <br /> 235 feet of leach line would be the minimum size of the system(3 lines of 78 feet plus pits). <br /> However, we understand that San Joaquin County Environmental Health Department has <br /> indicated to you that for the SDU,they desire three(3)leach lines of 95 feet with 42-inch <br /> diameter pits. No "double" system was required. <br /> The system was designed for no flow to seepage pits. Seepage pits should be utilized to <br /> provide system storativity during periods of peak flow. Please see the attached calculation sheets <br /> for equations,variables, and calculations. <br /> pL0.S0 <br /> i <br /> 2 <br /> 0 <br /> �JSOC\ <br />