Study of river bed lowering downstream of a dam using a mathematical model

This paper deals with a study of river bed lowering downstream of a completed dam. The dam is of the arch type (height: 155 m, crest length: 170 m, spillway discharge: 1500 m 3 /s), its objectives being power generation and irrigation. Due to the fact that sediment is trapped in the reservoir, the river bed downstream of the dam is being lowered. The riverine forest, which constitutes the major evergreen area of the plain located downstream of the dam, providing produce and fodder for the population and animals during the dry season, may be partly affected in case of excessive lowering of the river bed. Bed lowering and the effects of remedial measures are studied out with the help of a mathematical model of long-term river bed evolution. This mathematical model takes into account the main characteristics of the sediment, the river and the hydraulic conditions.