CIV E 444 - APPLIED HYDRAULICS
SPRING 2016
LAB No. 13 SOLUTION
- The Creager formula is: Qp = 46 C A0.894A - 0.048
Qp = 46 C (355)0.894 × (355) - 0.048
Assume the maximum value of C = 100.
Qp = 241,361 cfs [Creager]
For TR-55, assume T = 10000 yr; CN = 100 (the maximum); and ap = 0 (lowest diffusion).
Assume Type II storm, because for all other conditions being the same, it gives the highest peak (it is the most intense type storm).
Qp = 236,075 cfs [TR-55]
- α = [(∑ Ai )2 / (∑ Ki )3] [ ∑ (Ki3/ Ai2) ]
Conveyance K = (1.486/n) A R 2/3
The calculations are shown in the following table.
The wetted perimeter inbank is P = 100 + 2(10 - 2) = 116 ft.
The wetted perimeter in the flood plain is P = 500 + 2 = 502 ft.
i | Segment | B | d | V | n | A | P | R | R2/3 | K | K3/ A2
| 1 | Left flood plain | 500 | 2 | 2 | 0.05
| 1000 | 502 | 1.992 | 1.583 | 47,047 | 104,134,780
| 2 | Inbank channel | 100 | 10 | 5 | 0.03
| 1000 | 116 | 8.621 | 4.204 | 208,238 | 9,029,837,855
| 3 | Right flood plain | 500 | 2 | 2 | 0.05
| 1000 | 502 | 1.99 | 1.583 | 47,047 | 104,134,780
| | Sum | | | | | 3000 | | | | 302,332 | 9,238,107,415
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α = [(∑ Ai )2 / (∑ Ki )3] [ ∑ (Ki3/ Ai2) ] = [(3000)2/(302,332)3] [ 9,238,107,415 ]
α = 3.008
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