What are the types of open channel flow?

Open channel flow is classified by time and space variation: Steady vs Unsteady (depth changes with time), Uniform vs Non-uniform (depth changes along channel). Combinations: steady uniform (constant depth everywhere, like long canal), steady non-uniform (gradually or rapidly varied flow, like spillway), and unsteady non-uniform (flood waves). Also classified by Froude number: subcritical (Fr<1, tranquil), critical (Fr=1), and supercritical (Fr>1, rapid).