Document Type : Original Article
Authors
1
PhD Student, Faculty of Natural Resources, Ferdowsi University of Mashhad, Mashhad, Iran.
2
MSc Graduate, Islamic Azad University, Torbat-e Jam Branch, Torbat-e Jam, Iran.
3
PhD Graduate, Department of Arid and Semi-arid Regions, Faculty of Desert Studies, Semnan University, Semnan, Iran.
10.22075/ceasr.2025.38469.1056
Abstract
The growing global population and consumer-oriented lifestyles have led to the overexploitation of natural resources, resulting in reduced soil permeability, vegetation degradation, increased flooding, erosion, sedimentation, and drought. To address these challenges, watershed management operations have been implemented in Iran; however, comprehensive evaluations are still limited. This study evaluates the effects of mechanical watershed management structures on runoff storage and flood reduction in the Karizak watershed, located in Khalilabad County, Razavi Khorasan Province.
Topographic data, slope, and elevation classes were extracted using a digital elevation model (DEM), and field surveys documented the features of nine earthen and four gabion check dams. Infiltration rates were measured using double-ring infiltrometers in both sediment-laden and sediment-free zones. Water infiltration and evaporation volumes were estimated at 10-day intervals from the time of structure construction through the end of the 2018–2019 water year.
The results showed significantly reduced infiltration in sediment-laden areas due to pore blockage by fine particles. In total, approximately 10 million cubic meters (92%) of floodwater infiltrated, while 0.9 million cubic meters (8%) evaporated. The high infiltration efficiency is linked to rainfall timing (April–mid-June) when temperatures are lower. The structures successfully reduced peak flood discharge and enhanced groundwater recharge via qanats. Nonetheless, issues related to improper siting and structural dimensions were observed. The cost-benefit ratio was 10.6 for mechanical measures and 4.9 for the entire watershed, indicating economic feasibility.
Overall, these operations significantly improved water infiltration and flood control. Continued assessment and optimized design are crucial for enhancing watershed management effectiveness.
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