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OSTP Mound Design UNIVERSITY <br /> Minnesota Pollution MINNESOTA ilithil,,„4" <br /> Control Agency Worksheet >1 °/0 Slope �.� <br /> 1. SYSTEM SIZING: Project ID: v 06.12.13 <br /> A. Design Flow: 750 GPD TABLE IXa <br /> z LOADING RATES FOR DETERMINING BOTTOM ABSORPTION AREA <br /> B. Soil Loading Rate: 0.60 GPD/ft AND ABSORPTION RATIOS USING PERCOLATION TESTS <br /> Treatment Level C Treatment Level A,A-2,8, <br /> C. Depth to Limiting Condition: 2.0 ft <br /> Absorption Absorption <br /> Percolation Rate Mound Mound <br /> (MPI) <br /> Area Loading Absorption <br /> Loading Absorption <br /> D. Percent Land Slope: 3.0 % Rate Rate <br /> ( d ,) Ratio (phi) Ratio <br /> E. Design Media Loading Rate: 1.2 GPD/ft2 <br /> <01 1 _ 1 <br /> F. Mound Absorption Ratio: 2.00 0.1 10 5 1.2 1 1.6 1 <br /> 0 1 to 5(fine sand 0.6 2 1 1.6 <br /> Table I and loamy fine sand) <br /> MOUND CONTOUR LOADING RATES: 6 to 15 0.7e 1.5 1 1.6 <br /> Contour 16 to 30 0.6 2 0.78 2 <br /> Measured Texture-derived 31 to as 0.5 2.4 0.78 2 <br /> Parc Rate OR mound absorption ratio Loading <br /> Rate: 46 to 60 0.45 2.6 0.6 2.6 <br /> 60nlpi 1.0, 1.3. 2.0,2.4.2.6 . .12 61 to 120 5 0.3 5.3 <br /> < <br /> >120 - - - <br /> 61-120mpi OR 5.0 • sl2 <br /> *Systems with these values are not Type I systems. <br /> 120 mpi 5.0 _6. Contour Loading Rate (linear loading rate)is a <br /> 2recommended value. <br /> 2. DISPERSAL MEDIA SIZING <br /> A. Calculate Dispersal Bed Area: Design Flow-Design Media Loading Rate =ft2 <br /> 750 GPD 1.2 GPD/ft2 = 625 ft2 <br /> If a larger dispersal media area is desired, enter size: 630 ft2 <br /> B. Enter Dispersal Bed Width: 10.0 ft Can not exceed 10 feet <br /> C. Calculate Contour Loading Rate: Bed Width X Design Media Loading Rate <br /> 10 ft2 X 1.2 GPD/ft2 = 12.0 gal/ft Can not exceed Table 1 <br /> D. Calculate Minimum Dispersal Bed Length: Dispersal Bed Area + Bed Width = Bed Length <br /> 630 ft2 s 10.0 ft = 63.0 ft <br /> 3. ABSORPTION AREA SIZING <br /> A. Calculate Absorption Width: Bed Width X Mound Absorption Ratio =Absorption Width <br /> 10.0 ft X 2.0 = 20.0 ft <br /> B. For slopes>1%, the Absorption Width is measured downhill from the upslope edge of the Bed. <br /> Calculate Downslope Absorption Width: Absorption Width - Bed Width <br /> 20.0 ft - 10.0 ft = 10.0 ft <br /> 4. DISTRIBUTION MEDIA: ROCK <br /> A. Media Volume: Media Depth X Length X Width <br /> 1.00 ft X 63.0 ft X 10.0 ft= 630 ft3 s 27 = 23 yd3 <br />