What do you use to measure the hydraulic radius or a river?

Question

What do you use to measure the hydraulic radius or a river?

Answer 1

The hydraulic radius is defined as:

    Rh = A/P

where:

    Rh is the hydraulic radius (m)

    A is the cross sectional area of flow (m2)

    P is wetted perimeter (m)

The hydraulic radius is not half the hydraulic diameter, despite what the similarity in the names may suggest. It is a function of the shape of the pipe, channel, or river in which the water is flowing. In wide rectangular channels, the hydraulic radius is approximated by the flow depth.

http://en.wikipedia.org/wiki/Hydraulic_r...