CIV E 530 - OPEN-CHANNEL HYDRAULICS
SPRING 2005
HOMEWORK No. 6

(25 percent) Given the following design specifications: Q = 300 cfs; b = 16 ft; z = 2; and n = 0.014. What channel slope is necessary (use two significant digits) to set the normal depth not to exceed 2.5 ft?
(25 percent) Given the following design specifications corresponding to the Chasma-Jhelum Link Canal, in Pakistan: Q = 27,000 cfs; b = 380 ft; z = 3.0; and S_o = 0.00022. What is the value of Manning's n (use two significant figures) that will keep the normal depth below 14 ft?
(25 percent) Given the following data for three trapezoidal channels:

Type Q (m³/s) z S_o n V_max (m/s)

I 25 2.0 0.0077 0.045 1.6

II 350 2.5 0.0021 0.035 2.0

III 1,200 3.0 0.0005 0.027 1.8

in which V_max = maximum permissible velocity. What is the design bottom width (with accuracy to within one-tenth of a meter) required to satisfy the specified maximum permissible velocity?
(25 percent) Given: Q = 500 cfs; S_o = 0.0028; and n = 0.024. Using the permissible tractive force method, design a trapezoidal channel section for the following conditions:
(a) z = 3.0; noncohesive material, slightly angular in both sides and bottom d₂₅ = 1 in.
(b) z = 2.5; noncohesive material, slightly angular in sides, d₂₅ = 1 in; noncohesive material in bottom with d₅₀ = 1 mm, canal with high content of fine sediment in the water..