CE 4200 Chapter : Homework 6 Solution 2017 Fall
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Problem 1 solution: (1) total rainfall up to 60 min is (1. 143+1. 893+7. 375+2. 955+1. 413) in/hr *12 min = 2. 956 in (2) cn=1000/(10+0. 0394s)=70. 86. For the parking lots and the buildings, the curve number is 98. For the grassed area (type a soil in good condition), the curve number is 39. (1) area-weighted curve number: Using the concave method, the figure below shows the baseflow separation. The inflection point is at the 6th day. The table below shows the calculation of direct runoff (m3/s) for each day. The total volume of direct runoff is 180,316,800 m3. (2) (3) (4)=(2)-(3) (4)*86400. Problem 5 solution: (1) let d be the water depth in the channel. The wetted area is a=0. 2d and the wetted perimeter is. 0. 2 d solving this equation, the water depth is 0. 12 m. V q a (3) (4) tc=l/v=60/0. 83=72 s = 1. 2 min.
