8.5.1. Regime Methods Regime Methods for the design of stable channels were first developed by the British engineers working for canal irrigation in India in the nineteenth century. At that time, the problem of sediment deposition was one of the major problems of channel design in India. In order to find a solution to this problem, some of the British engineers studied the behaviour of such stretches of the existing canals where the bed was in a state of stable equilibrium. The stable reaches had not required any sediment clearance for several years of the canal operation. Such channels
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were called regime channels. These channels generally carried a sediment load smaller than 500 ppm. Suitable relationships for the velocity of flow in regime channels were evolved. These relationships are now known as regime equations which find acceptance in other parts of the world as well. The regime relations do not account for the sediment load and, hence, should be considered valid when the sediment load is not large.
