# Mean Depth

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Mean depth, abbreviated as $$h_m$$, is the average water depth in a stream channel or conduit computed by dividing the cross-section area by the surface width.

### Mean Depth FORMULA

$$\large{ h_m = \frac{ A_c }{ T } }$$

$$\large{ h_m = \frac{ v^2 }{ g \; Fr^2 } }$$     (Froude number)

Where:

$$\large{ h_m }$$ = mean depth

$$\large{ A_c }$$ = area of cross-section of flow

$$\large{ Fr }$$ = Froude number

$$\large{ g }$$ = gravitational acceleration

$$\large{ T }$$ = top of water surface width

$$\large{ v }$$ = velocity of flow

Solve for:

$$\large{ T = \frac {A_c} { h_m } }$$