# Hydraulic Radius of a Trapezoidal Channel (Equal Side Slopes)

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Hydraulic radius, abbreviated as $$r_h$$, is the area cross-section of water in a pipe or channel divided by the wetting perimeter.

## Hydraulic Radius of a Trapezoidal Channel (Equal Side Slopes) formula

 $$\large{ r_h = \frac { h \; \left( b \;+\; z\; h \right) } { b \;+\; 2\;h \; \sqrt { 1 \;+\; z^2 } } }$$

### Where:

$$\large{ r_h }$$ = hydraulic radius

$$\large{ b }$$ = bottom width of fluid

$$\large{ h }$$ = depth of fluid

$$\large{ z }$$ = width of channel slope