Multiple choice

A steep wide rectangular channel takes off from a reservoir having an elevation of 101.2 m. At the entrance, the bottom elevation of the channel is 100 m. If the slope of the channel is increased by 4%, the discharge per unit length in the channel will be

  1. 2.24 m2/s

  2. higher than 2.24 m2/s by 4%

  3. higher than 2.24 m2/s by 2%

  4. choked
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In a steep channel, flow is often governed by normal depth. Using Manning's equation, Q is proportional to the square root of the slope. A 4% increase in slope leads to a 2% increase in discharge.

Keep practicing — related questions