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�Ns�rE a �,� <br /> se,�,.aGc '���-_ rockbed#1 _ ,., `:� Job# L2 61 <br /> TR.EATMlfJT __r-_�a_�_ <br /> PR�O6RAM � __ ' <br /> University of Minnesota Mound Design Worksheet <br /> Greater than 1%Slopes � <br /> A FLOW <br /> Es6mated 750 gpd(see figure A-1) <br /> or measured x 1.5(safety factor}= 0 gpd <br /> B. SEPTIC TANK LIQUID VOLUMES <br /> Septic tank capacity 3000 gallons(see figure G9) <br /> Number of tanks/compartments 0 <br /> Effiuent Filter (yes/no) no <br /> C-1 Septic Tank Capacity in Gallons <br /> Number of Minimum Capacity with Capacity with <br /> Bedrooms Capacity Garb.Disp. Disp.and Lift <br /> 2 or less 750 1125 1500 <br /> 3 or 4 1000 1500 2000 <br /> 5 or 6 1500 2250 3000 <br /> 7,8 or 9 2000 3000 4000 <br /> �. SOILS(Site evaluation dafa) <br /> 1. Depth to restricting layer- 1.5 feet <br /> 2. Depth of percolation tests= 12 inches <br /> 3. Texture loam <br /> 4. Soil loading rate(see Figure D-33J 0.60 gPd/ft2 <br /> Percolation rate � � MPI <br /> 5. %L.2nd Slope 12.0 % <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply average design flow(A)by 0.83 to obtain required area of roc;k layer:Item A x 0.83= <br /> 750 gpd x 0.83 ft/gpd= 630 ft <br /> 2. Determine rock layer width =0.83 ft`lgpd x Linear Loading Rate(LLRj(see LLR chart) <br /> 0.83 ft�/gpd x 12.(?0 = 10.0 ft <br /> LLR Chart <br /> Perk Rate LLR <br /> <120 MPI <=12 <br /> >=120 MPI <=6 <br /> 3. Length of rock layer=area divided by width= <br /> 630.0 ft/ 10.0 feet= 40.0 ft <br /> E. ROCK VOLUME <br /> 1. Multiply rock area by rock depth to get cubic feet of rock <br /> 630.0 X 1.0 ft= 630.0 ft3 <br /> 2. Divide ft3 by 27 ft3/yd'to get cubic yards <br /> 630.0 ft3 / 27 = 23.3 yd3 <br /> 3. Multiply cubic yards by 1.4 to get weight of rocic in tons; <br /> 23.3 yd3 X 1.4 ton/yd3 = 32.7 tons <br /> Page 1 of 5 <br />