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کلیدواژهها
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Flow simulation, WEAP model, Water resources management, Land Use/Land Cover (LULC), Curve Number (CN), Dukan Dam, Sardasht Dam, Remote sensing (RS) .
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چکیده
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In response to the rapid growth of urbanization, the expansion of anthropogenic activities, and the intensification of climate change, many watersheds have experienced profound transformations in their ecological structure, land use patterns, and hydrological regimes. The upper basin of the Little Zab River—one of the primary tributaries of the Tigris River—plays a vital role in water supply, groundwater recharge, and maintaining the environmental balance of northern Iraq and adjacent border regions of Iran. This study aims to quantitatively assess the impacts of the Sardasht Dam construction, as well as the broader hydrological changes induced by dam operations and management scenarios, on the surface water resources of the basin. Scenario-based optimization strategies for water resource management are developed using the WEAP model. Primary data were compiled through a combination of field measurements, RS, and satellite image processing in the Google Earth Engine environment, complemented by spatial analysis in ArcGIS. Physiographic analysis revealed an elevation range of 3,189 meters and an average basin elevation of 1,388 meters. The hypsometric curve analysis indicated a geomorphological mature basin, where erosion processes play a dominant role in reducing runoff potential. Land cover monitoring from 2017 to 2024 showed a significant decrease in barren lands (64.5%) and an increase in urban (52%), agricultural (13.6%), and forest–orchard areas (37%), leading to a slight increase in the (CN) (CN) and enhanced runoff potential. The mean annual precipitation in the basin was estimated at approximately 670.86 mm. The processed data were input into the WEAP model, and the inflow to the Dokan Dam was simulated for the period 2010–2023 with high accuracy (R² = 0.997; RMSE < 3%). Regional water demand and cropping patterns were modeled using CROPWAT and CLIMWAT datasets. Four management scenarios were developed and evaluated, including temperature increase, irrigation efficiency improvement, cropping pattern modification, and optimized reservoir release. The results revealed that a projected temperature rise of 0.8°C by 2029 would lead to an average annual reduction of 152.45 million cubic meters in dam inflow. Conversely, increasing irrigation efficiency to 70%, revising cropping patterns, and optimizing water releases would result in additional inflows of 116.48, 151.67, and 65.6 million cubic meters per year, respectively.
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