Question

The critical depth of water flowing through a rectangular channel of width 5 m when discharge is $12.5m^3/s$ is

• A. ${\left(0.46\right)}^{1/3}m$
• B. ${\left(0.64\right)}^{1/3}m$
• C. ${\left(16\right)}^{1/2}m$
• D. ${\left(2.25\right)}^{1/2}m$

Answer 1

The correct option is B ${\left(0.64\right)}^{1/3}m$

Discharge per unit width

q = 12.5/5

=$2.5m^3/s/m$

Critical depth,

$y_c={\left(q^2/g\right)}^{1/3}={\left(0.64\right)}^{{}^{1/3}}$