Effect of reservoir geometry on functionality of recharge dams influenced by sedimentation: case study of the Meymand recharge dam

Autor: Jahanshir Mohammadzadeh-Habili, Maryam Soltani, Davar Khalili
Rok vydání: 2021
Předmět:
Zdroj: Arabian Journal of Geosciences. 14
ISSN: 1866-7538
1866-7511
DOI: 10.1007/s12517-021-06903-z
Popis: In the present study, influence of reservoir geometry on sedimentation pattern and functionality of the Meymand recharge dam, located in a semi-arid region in southern Iran, is studied. After 7 years of dam operation and sedimentation, the reservoir functionality was evaluated during 2018–2019 water year, which discharged ~ 813700 m3 of floodwater into the reservoir. Field measurements supported by isotope and hydro-chemical tracing indicated that most of inflow floodwater (94%) recharged the aquifer through the reservoir bed, resulting in ~ 33.63-m groundwater table rise in the downstream aquifer. Based on field mapping, accumulated sediments on reservoir bed covered only ~ 9.3% of reservoir surface area. Numerical simulation using Seep2D revealed that due to very low permeability, accumulated sediments acted as a barrier against recharge from reservoir bed. Therefore, only permeability of ~ 9.3% of the Meymand reservoir surface area was influenced by sedimentation and the rest of the reservoir surface area (~ 90.7%) was not influenced by sedimentation. The V-shaped cross-sectional of the Meymand reservoir was instrumental in the formation of the minimal sedimentation coverage area, which consequently resulted in increased reservoir recharge efficiency. Because during dry periods, accumulated sediments on slopping sidewalls of reservoir bed are easily washed out and transported to the lowest area in reservoir bed for settlement. So, V-shaped alluvial valleys are suggested as suitable sites for recharge dams, which should be considered in new artificial recharge projects.
Databáze: OpenAIRE
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