Nonuniform Flow in Flat Rectangular Channels

Nonuniform flow is possible in flat open channels and the surface profile of flow in such a channel is always in the form of a backwater curve. The present practice for backwater profile computations either needs expensive computer time or it employs a very tedious manual trial and error method. An easy-to-use alinement chart is developed for determining surface profile of subcritical, gradually varied flow in flat rectangular open channels. The only parameter needed in applying the chart is the critical depth which can also be read from an auxiliary scale in the chart. Knowledge of nonuniform flow is not essential for using the chart. Numerical examples are included.