WORLD FOR CIVIL

Critical Depth of Open-Channel Flow

For a given value of specific energy, the critical depth gives the greatest discharge, or conversely, for a given discharge, the specific energy is a minimum for the critical depth.

For rectangular channels, the critical depth, dc ft (m), is given by

d_c =[Q²/b²g]^1/3

where
d_c =critical depth, ft (m)

Q= quantity of flow or discharge, ft³/s (m³/s)

B= width of channel, ft (m)