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- t Percolation testing was performed in accordance with San Joaquin County Department of Environmental Health regulations. The attached Site Plan denotes the location of the percolation trench test and the Field Test Data Sheet illustrates the perc test results. The subsurface soil strata indicate that seepage pits will have to be installed for each individual septic system. Additionally,the information obtained from the Environmental Health Department regarding the number of permits for repairs/additions also indicates the need for the installation of seepage pits. The perc test results reveal an initial rapid infiltration and percolation, which eventually decreases by approximately half, over the four-hour test period. It is to be noted, however, that the test pit was terminated at 20 feet and not 25 feet, as a safety factor. The Environmental Health Department allows seepage pits to extend to a depth of 25 feet which will allow for significantly greater percolation of septic effluent. The water drop for the last half-hour of the four-hour test period was 2.6 inches, which translates to a pert rate of 11.5 minutes/inch (min/in). This can be considered a comparatively rapid perc rate. The trench pump-in test calculations demonstrate an acceptance rate (AR) in gals/sq ft/day as follows: ❑ Length of trench= 12 ft ❑ Width of trench=2 ft ❑ Depth of trench=20 ft ❑ Depth of water maintained on the floor of trench=2 ft ❑ Depth below bottom of trench at periphery of plume =4 ft(est) ❑ Total water volume applied during test= 3 x 400 gal tank= 1200 gals ❑ Extent of water plume area: water surface=2 ft x 6 ft .•. plume area is estimated to be: 10 ft width x 14 ft length= 140 sq ft ❑ Acceptance Rate (AR) =total flow absorbed- (area)(time) ❑ AR= 1000 gals_ (140 sq ft)(4 hrs - 24 hrs/day) =43 gals/sq ft/day Theoretical Effluent Acceptance: If the bottom 5 feet of a 36 in dia seepage accepts effluent at the calculated rate, each seepage pits will initially accept 54 sq ft x 43 gals/sq ft/day=2327 gals/day. The following calculations show leachline and seepage pit requirements for a typical Milk Barn bathroom: 1200 Base Tank Capacity (BTC) + 15 gal/person/shift x 2 shifts x 6 people = 180 gals average daily flow(ADF) = 1200 + 180= 1380 Calculated Tank Capacity (CTC). 1380 x 0.250 soil factor= 345 lineal feet of leachline. Therefore: two-one hundred foot leachlines may be used in conjunction with two 36 in dia x 25 ft deep seepage pits at the ends of each leachline: 200 lineal feet+2 x 60 ft leachline equivalent for two pits= 320 ft of leachline. The final length of leachline and number of seepage pits for each residence will be dependent the number of bedrooms and the number of people who will occupy the residence. 3 Vaffey Ag Ppearch