Document Type : Research Paper
Authors
- Seyedsaeid Nabavi 1
- Arash Malekian 1
- Naser Mashhadi 2
- Khaled Ahmadaali 3
- Raoof Mostafazadeh 4
- Ali Shabazi 5
1 Department of Reclamation of Arid & Mountainous Regions, Faculty of Natural Resources, University of Tehran, Karaj, Iran
2 International Desert Research Center, University of Tehran, Karaj, Iran
3 Department of Irrigation and Reclamation, Faculty of Agriculture, University of Tehran, Karaj, Iran
4 Department of Natural Resources, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
5 Natural Resources and Watershed Management Organization of Alborz Province, Karaj, Iran
Abstract
The Baliqlu Chay River watershed in Ardabil Province is a key water source for regional demands. In this study, the role of climate change and human activities on streamflow is examined by using hydrological indices and trend analysis over the period 1991-2021. Monthly, seasonal, and annual climatic and discharge variables were assessed for trends using the Mann-Kendall trend test and Sen's slope estimator. Results indicate streamflow is controlled by seasonal snowmelt, groundwater reliance, and the controlling impact of the Yamchi Dam. Moreover, the high flow variability observed at the Yamchi Station, as indicated by elevated standard deviation and coefficient of variation values, suggests an increased risk of flooding in this area. Trend analysis results over the 30-year statistical period reveal a decreasing trend in annual precipitation at the Ardabil and Nir stations, although these trends are not statistically significant at the 99% and 95% confidence levels. In contrast, a statistically significant increasing trend in annual precipitation was detected at the synoptic station in Sareyn at the 99% confidence level. Additionally, the annual temperature increase at all stations was found to be statistically significant at the 99% confidence level. The assessment of streamflow trends on an annual scale at the Nirchay and Yamchi Dam hydrometric stations indicates a statistically significant decreasing trend at the 1% level (p-value ≤ 0.01). These results emphasize the urgent need for sustainable water management strategies, including optimization of resource use, revised consumption patterns, and improved operation of the Yamchi Dam. Such interventions are essential to reduce the negative impacts of climate change and anthropogenic pressures on the river’s hydrological regime.
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