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� OSTP Trench Design <br /> UNIVERSITY <br /> Minnesota Pollutbn Worksheet OF MINNESOTA <br /> Control Agency <br /> 1. SYSTEM SIZING: Project ID: v 05.31.13 <br /> A. Design Flow: 450 GPD <br /> B. Code Maximum Depth: 12 inches Designers Maximum Depth:�inches <br /> C. Soil Loading Rate: 1.67 GPD/ftZ Contour Loading Rate: �8a1/ft <br /> D. Required Bottom Area: Design Flow(1.A)=Loading Rate(1.C)= Initial Required Bottom Area <br /> 450 GPD= 1.67 GPD/ftZ = 269 ftZ <br /> E. Select Dispersal Media: ❑ROCk <br /> (selection required) �Registered Product <br /> F. Select Distribution Method: ❑PI'255U�@ �Gravity-Drop Box <br /> O Gravity-Other Chamber <br /> G. If distribution media is installed in contact with sandy or loamy sand or with a percolation rate of 0.1 to 5 mpi <br /> indicate distribution or treatment method: <br /> 2. TRENCH CONFIGURATION: ROCK <br /> p. Initial required Sidewall Design <br /> trench bottom area Absorption Bottom Area Bottom Area trench 1 �` � <br /> (ftZ): (from 1.D) (inches) Reduction Multiplier bottom area <br /> Cover <br /> 6to11 1 <br /> Q W Distribution <br /> 12 to 17 20% 0.8 ��'���� <br /> 18 to 23 34% 0.66 srdewau <br /> 24 40% 0.6 <br /> B. Select Sidewall Height: �inches = �ft wtdth <br /> C. Design Bottom Area(2.A): �ftZ <br /> D. Select Trench Width: �ft <br /> E. Total Designed Trench Length: Bottom Area =Trench Width =Total Required Trench Length <br /> �ftZ �C� ft= �ft <br /> I. Calculate Minimum system length based on Contour Loading Rate: Design Flow =Contour Loading Rate = <br /> ���-��al/ft = �ft <br /> F. Select No. of Trenches: �trenches <br /> G. Select Trench Spacing: �ft (typically 5- 12 ft from center to center) <br /> H. Calculate Lawn Area: Trench Length(2.E)X Trench Spacing(2.G)=square feet of lawn area <br /> � ft X�ft = �ftZ lawn area <br /> J. Select Depth Required to Cover Distribution Pipe: <br /> �ft (0.33 ft for pressure,0.5 ft for gravity) <br /> K. Calculate Rock Volume: (Sidewall Height(2.6)+Depth to Cover Pipe(2.J))X Bottom Area(2.C)=cubic feet <br /> ( �ft +�ft) X�ftZ =�ft3 <br /> Divide ft3 by 27 ft3/yd3 to calculate cubic yards: <br /> �ft3 + 27 = �yd3 <br />