13.2. LOCATION OF HEADWORKS ON RIVERS Larger rivers, generally, have four stages, viz., the rocky, boulder, trough (or alluvial) and delta stages. Of these, the rocky and delta stages are generally unsuitable for siting headworks. Usually, the command area is away from the hilly stage, and it would, therefore, involve avoidable expenditure to construct a channel from headworks located in the hilly stage to its command area. In the delta stage, the irrigation requirements are generally less and also the nature of the river at this stage poses other problems.
The boulder and alluvial stages of a river are relatively more suitable sites for locating headworks. The choice between the boulder stage and the alluvial stage is mainly governed by the command area. If both stages are equally suitable for siting the headworks from command area considerations, the selection of the site should be made such that it results in the most
