Influence of aspect ration in a Rectangular Shallow Reservoir on distribution of Sedimentation concentration

Document Type : Research Paper

Authors

1 خیابان نبوت بین حضرت رسول و بهشتی مجتمع سپهر واحد۲

2 Associate Professor, Civil Engineering Department, Jundi-Shapur University of Technology, Dezful, Iran

Abstract

Sediment deposition in settling basins is one of the critical and fundamental challenges in water resource management. This phenomenon can lead to the accumulation of sediments in water reservoirs, reduced storage capacity, increased flood risks, and water pollution. Therefore, understanding the governing processes of sediment deposition in basins and reservoirs, and optimizing the design of these structures, are of utmost importance. In this research, the effect of the aspect ratio (length-to-width ratio) of a reservoir on the distribution of suspended sediment concentration under free-flow conditions was investigated. Using rectangular reservoirs with aspect ratios of 1, 2, and 4, the rate of sedimentation under different hydraulic conditions was evaluated. This parameter is recognized as one of the most influential factors on the flow pattern and sedimentation in settling basins. The results showed that the aspect ratio of the reservoir is directly related to the distribution of suspended sediment concentration. Reservoirs with a higher aspect ratio (such as the reservoir with a shape factor of 4) retain a higher amount of suspended sediments on their surface. Furthermore, in settling basins with a high shape factor, the lateral expansion of the density current relative to its longitudinal expansion creates a more favorable condition for the uniform distribution of sediments. In contrast, in basins with a low shape factor, the longitudinal expansion is greater, and the probability of the formation of recirculating flows increases. These findings suggest that considering the aspect ratio as a key parameter in the design of sedimentation basins can significantly contribute to improving the performance and efficiency of these structures in sediment management.

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Articles in Press, Accepted Manuscript
Available Online from 11 January 2025
  • Receive Date: 23 September 2023
  • Revise Date: 08 January 2025
  • Accept Date: 11 January 2025
  • Publish Date: 11 January 2025