Irrigation Sciences and Engineering

Irrigation Sciences and Engineering

Investigation the effect of aspect ratio of shallow reservoirs on distribution of suspended sediment concentration

Document Type : Research Paper

Authors
Mohammad Afrashteh 1
Babak Lashkar-Ara 2
1 Master Geaduate, Civil Engineering Department, Jundi-Shapur University of Technology, Dezful, Iran.
2 Assistant Professor, Department of Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran (
10.22055/jise.2025.44838.2094
Abstract
Sedimentation in settling basins is one of the significant challenges in water resource management. This phenomenon can lead to sediment accumulation in water reservoirs, reduced storage capacity, increased flood risks, and water pollution. Therefore, understanding the processes governing sedimentation in basins and optimizing the design of these structures is of great importance. In this research, the impact of aspect ratio (length to width ratio) of the reservoir on the distribution of suspended sediment concentration under free flow conditions has been investigated. Using rectangular tanks with aspect ratios of 1, 2, and 4, the sedimentation rate under various hydraulic conditions was evaluated. This parameter is recognized as one of the most critical factors affecting flow patterns and sediment deposition in settling basins. The results indicated a direct relationship between the aspect ratio of the reservoir and the distribution of suspended sediment concentrations. Specifically, reservoirs with higher aspect ratios (such as a tank with an aspect ratio of 4) retain greater amounts of suspended sediments on their surfaces. Additionally, in settling basins with high aspect ratios, the lateral spreading of dense flow creates a more favorable condition for uniform sediment distribution compared to its longitudinal spreading. Conversely, in basins with lower aspect ratios, greater longitudinal spreading occurs, increasing the likelihood of backflow formation. These findings demonstrate that considering the aspect ratio as a key parameter in the design of settling basins can significantly enhance the performance and efficiency of these structures in sediment management.
Keywords
Shallow reservoirs
sedimentation
aspect ratio
reservoir geometry
Subjects
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Irrigation Sciences and Engineering
Volume 48, Issue 3
Autumn 2025
Pages 55-73

  • Receive Date 23 September 2023
  • Revise Date 10 December 2023
  • Accept Date 26 November 2023
  • Publish Date 05 November 2025