Sediment transport applications in irrigation canals

Sediment transport in irrigation canals is an important issue in the design and operation of irrigation systems. Frequently observed problems in irrigation systems are, for example, clogging of turnouts and reduction of the conveyance capacity of canals by siltation, and instability of side slopes and of structures due to erosion. Each year large investments are required to maintain or to rehabilitate these systems and to keep them in an acceptable condition for irrigation purposes. Irrigation canals are generally designed based on the assumption of uniform and steady flow of water and sediments. However, the flow is predominantly non-uniform, due to time-dependent discharges and constant water levels at regulation and division points. A strong relationship exists between the sediment transport and flow conditions. The aim of this article is to present some new developments in the behaviour of sediment and associated sediment transport in irrigation canals under changing flow conditions, as well as the deposition and/or entrainment rate in time and place for various flow conditions and sediment inputs. This article will discuss an approach to compute sediment transport in irrigation canals under non-uniform flow conditions. The sediment transport has been analysed for the flow conditions that prevail in irrigation canals. The Ackers-White and Brownlie equations are recommended to compute the sediment transport under equilibrium conditions for prismatic canal cross-sections. For non-equilibrium conditions, a numerical solution of Galappatti's depth-integrated model is applied. Copyright (C) 2002 John Wiley Sons, Ltd.