Waters flowing in streams and rivers have the ability to scour channel beds, to carry particles (heavier than water) and to deposit materials. This phenomenon of sediment transport can affect substantially the design of reservoirs. The paper describes four case studies of siltation which rendered useless water storage structures in less than 25 years. Although each dam had advanced structural features, the hydrology of the catchment and sediment transport processes were not properly taken into account. The study highlights practical situations in which a reservoir must be analysed as a complete system, taking into account structural features, hydraulics, hydrology, sediment transport, catchment erosion and catchment management. The case studies may used as teaching examples to increase student interest on the significance of sediment transport problems and to emphasise the design procedure to professionals. They may serve also to alert the community at large to basic errors caused by improper soil conservation policy and the inability to predict sediment-load process.
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