Transport et dépôt de sédiments en canaux d'irrigation : une méthodologie pour modéliser les processus

A methodology for sediment transport and deposition modeling in irrigation canals

CEMAGREF, UR Irrigation, BP 5095, 34033 Montpellier Cedex l, France

Abstract

In semi-arid areas - where rivers convey high sediment loads - the irrigation canals are often faced with deposition. The bed aggradation can affect the conveyance capacity of the canals and/or disturb the water distribution. The current sediment control methods are generally insufftcient and, most of the time, design and management strategies could be improved. Mathematical modeling may be a good tool to choose appropriate strategies. Observations conducted on various irrigation systems have led to the development of a specific module. SEDI, as part of a one-dimensional hydrodynamic model dedicated for irrigation canals. The model is based on physical concepts, but remains simple enough to allow practical applications and long term simulations. A set of guidelines to address study cases is provided and illustrated on a secondary canal of Pakistan where the model is calibrated and validated. The model can be used, then, to compare different management scenarios or highlight design problem.