A winding natural stream with weeds has an average depth of 0.86m and is 7.25m across. The stream channel drops 0.34 m/km. What is the stream’s average velocity?

Answer 1

You should have been provided with a graph based upon actual data. There is no simple formula to apply to this question. The facts that the stream winds and is weed filled affect the answer.

Use the graph provided, or search for one online. I will see what I can find and post it later, if I find anything

Answer 2

Refer to sources that discuss the Mannong Equatiion, such as
http://www.lmnoeng.com/manning.htm
Different constants k apply to different situation.