Classification of Management Alternatives to Combat Reservoir Sedimentation

Abstract

Sedimentation is steadily depleting reservoir capacity worldwide, threatening the reliability of water supplies, flood control, hydropower energy and other benefits that form the basis of today’s water-intensive society. The strategies available to combat reservoir sedimentation may be classed into four broad categories. Three proactive categories seek to improve the sediment balance across reservoirs by: (a) reducing sediment yield from the watershed, (b) routing sediment-laden flows around or through the storage pool, and (c) removing deposited sediment following deposition. The fourth category (d) consists of strategies that adapt to capacity loss, without addressing the sediment balance. Successful management will typically combine multiple strategies. This paper presents a comprehensive classification of both proactive and adaptive strategies, consistent with current international practice. Functional descriptions and examples are given for each strategy, and criteria are provided to differentiate between them when there is potential for ambiguity. The classification categories can be used as a checklist of strategies to consider in evaluating sediment management alternatives for new designs as well as remedial work at existing sediment-challenged reservoirs. This will also help practitioners to more clearly describe and communicate the nature of their management activities. Widespread application of both active and adaptive strategies is required to bring sedimentation under control to sustain benefits of water storage for today’s and future generations.