Introducing a New Dam-Type Sediment Excluder Method at Dam Reservoirs for Sediment Mitigation

Document Type : Research Article

Authors

1 MSc. Graduate of Water Structures Engineering, Water Engineering Department, Shiraz University, Shiraz, Iran

2 Professor of Water Engineering, Department, Shiraz University, Shiraz, Iran

Abstract

In this paper a new method for mitigation of dam reservoirs sedimentation is introduced and its performance is evaluated. This method includes a self-cleaning and permanent function structure resembling a short dam built across the rivers discharging into the dam reservoir. This structure, called Dam-Type Sediment Excluder (DTSE), extracts suspended sediment from flows upstream of reservoir through a middle opening (gate) and prevents entrance of sediments into the reservoir. In this study, using laboratory experiments, the efficiency of the proposed DTSE method was examined under three ratios input discharges, three middle opening relative heights and the output (bypass) to input flow rates of 0.1, 0.2 and 0.3. The results showed that: 1) the efficiency of the DTSE increased with increase of middle opening height, 2) increase of bypass flow ratio affects the model efficiency and sediment concentration of bypass flow in a positive and negative manner, respectively. Therefore, between three flow ratios, bypass flow ratio of 0.2 is the optimum one, due to the water loss of 20% and proper efficiency, 3) the maximum extraction efficiency of the model was found to be about 40% while the average optimal efficiency, for bypass flow ratio of 0.2, was about 26%. Therefore, the new DTSE method could be introduced as an effective method for sediment mitigation, in comparison to other reservoirs sedimentation mitigation methods such as density current venting with only 20% efficiency.

Keywords


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