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The collection of data for unsteady/non-uniform sediment transport rates in a river below a reservoir, which arrests sediment from upstream, is very difficult. The establishment of a model for the determination of these sediment transport rates is equally difficult but important for the safety of a structure below the reservoirs. An indirect technique based on continuity equation for sediment transport has been used to obtain such data for unsteady/non-uniform flow conditions. Based on these data and dimensional analysis, a relationship for determination of sediment transport rate below high capacity reservoirs under unsteady-non-uniform conditions has been proposed which gave very high efficiency when checked with the available data for such conditions. As a consequence, a relationship for extent of degradation has also been established. [ABSTRACT FROM AUTHOR]

Degradation in a homogeneous alluvial channel due to complete stoppage of sediment downstream of a high capacity reservoir has been studied empirically. Based on dimensional analysis, a method has been established for predicting transient bed profiles in degrading alluvial stream. In addition, prediction procedures for other degradation elements like maximum degradation at any time at upstream section and degradation extent has also been evolved. The prediction procedures when tested against known data gave satisfactory results. [ABSTRACT FROM AUTHOR]