Open-Channel Capacity Determination Using Hydraulic Performance Graph

A method for determining the flow carrying capacity of a channel system, capable of accounting for the interacting backwater effect among channel reaches and incoming lateral flow, is presented here. The method makes use of hydraulic performance graphs—a new tool for dealing with open-channel-flow problems. The hydraulic performance graph summarizes all the backwater profile information for a channel reach. As an illustration, the method is applied to evaluate the channel capacities of a portion of Boneyard Creek in the city of Urbana, Ill. The example demonstrates that the channel flow capacity is a function of the exit water level, of which the maximum normal flow capacity and the absolute maximum carrying capacity are special cases.