Question

The depth of flow in an alluvial channel is 1.5 m. If critical velocity ratio is 1.1 and Manning's constant n is 0.018, the critical velocity of the channel as per Kennedy's method is

• A. 0.713 m/s
• B. 0.784 m/s
• C. 0.879 m/s
• D. 1.108 m/s

Answer 1

The correct option is B 0.784 m/s

Critical velocity ratio,

m = 1.1

Depth, y = 1.5 m

As per Kennedy's equation,

$v=0.55m{y}^{0.64}$

$=0.55\times 1.1\times (1.5{)}^{0.64}$

$=0.784m/s$