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Septic Tank Hydraulic Detention Time Calculation Detention Time= 1200 gal septic tank capacity x 0.70(30%volume lost to sludge/scum accumulation) 2.5 (Peaking Factor)x 42 gals/day ADF Detention Time=_8 days. The minimum acceptable detention tinfs 1.0 days. Primary and 100% Replacement Effluent Disposal Areas As referenced, it is proposed to install one -40 ft conventional leachline with a three ft dia. seepage pit at the end of this line to serve the milk barn restroom. Considering a Long Term Acceptance Rate (LTAR) of effluent into the soil at 0.200 gals/ft /day, correlated with the combined surface areas of the 40 ft leachline and a three ft dia., 25 ft deep seepage pit, we find: 2 112 for trench sides and 2 ftZ for trench floor x 40 ft of leachline= 160 ft' Surface area of the seepage pit=243 ft' 0.200 gals/ft/day x (160 ftZ+ 243 ftz)= 81 gals/day that the soil-effluent interfaces of the leachline trench and seepage pit soils can theoretically accept and manage at the mature state of the disposal system. This acceptance is over the calculated ADF by: 81 -42= 39 gals/day. ' The 100%reserve/replacement area is denoted on the plans and is located directly to the east of the primary disposal area where ample reserve/replacement area exists. III. CONCLUSIONS EHD typically requires an equivalent minimum of 300 lineal feet of leachline (LFLL)for commercial septic systems that possess sufficient disposal area to accommodate this minimum. However, facilities where wastewater flows will be unquestionably small, the EHD requires a civil engineer to adequately design and justify the septic system to manage these anticipated low _ effluent flow volumes. The pre-soak, or pre-saturation procedure before the percolation test, reveals the native soil at anticipated leachline depth has initial infiltrative and percolative capacities even under near saturated soil conditions from recent rains. As the soil becomes truly saturated, as demonstrated by the percolation testing, percolation almost entirely ceases. Filter fabric must be installed over the leachline trench and over the seepage pit after drain rock installation to alleviate rainwater intrusion and siltation of these structures. The 2012 Lines of Equal Depth Map published by the County indicates the depth to groundwater in this locale is approximately 70 ft. This maintains an ample separation distance between the bottom of the seepage pit and the depth to the water table. The installation of the proposed septic system must adhere to all requirements promulgated in the San Joaquin County Onsite Wastewater Disposal Standards. Page-4-