Question: i am interested in finding b i can solve for...

4. A trapezoidal channel has a bottom width of 20 feet, has side slopes of 2H:1V, and carries a flow of 750 ft3/s. a. Find th

I am interested in finding b. I can solve for a but i'm getting negative flow depths for part b. Thank you!

Slope is not given, but you would assume that at the head of a steep slope the flow is critical.