This document discusses different types of open channel flow. There are four main types: steady and unsteady flow, uniform and non-uniform flow, laminar and turbulent flow, and critical, sub-critical and super-critical flow. Steady flow has constant flow parameters over time, while unsteady flow has parameters that change over time. Uniform flow has constant velocity and depth along the channel, whereas non-uniform flow has varying parameters. Laminar flow has a Reynolds number below 500-600 and turbulent flow is above 2000. Critical flow has a Froude number of 1, sub-critical is below 1, and super-critical is above 1.