Question

Water flows in a rectangular, concrete, open channel which is 12 m wide at a depth of 2.5 m. The channel slope is 0.0028, and the manning coefficient is 0.013. the velocity of flow (in m/sec) is

• A. 5.945

Answer 1

The correct option is A 5.945
Given:

b = 12m,
d = 2.5
S = 0.0028,
n = 0.013

Velocity of flow, $V=\frac{1}{n}{R}^{2/3}{S}^{1/2}$

$R=\frac{A}{p}=\frac{bd}{b+2d}=\frac{12\times 2.5}{12+(2\times 2.5)}=1.765m$

$V=\frac{1}{0.013}\times (1.765{)}^{2/3}\times (0.0028{)}^{1/3}$

= 5.945 m/sec