Runoff and sediment dynamics modeling for erosion risk reduction and sustainable watershed management
نویسندگان
1 Department of Building and Construction, Technical Engineering College of Mosul, Northern Technical University, Mosul 41002, Iraq
2 Department of Land, Water and Environment, The University of Jordan, Amman 11942, Jordan
3 Department of Civil Engineering, The University of Jordan, Amman 11942, Jordan
4 Department of Land, Water and Environment, The University of Jordan, Amman 11942, Jordan
5 Department of Civil Engineering, The University of Jordan, Amman 11942, Jordan
6 Department of Civil Engineering, The University of Jordan, Amman 11942, Jordan
7 Department of Civil Engineering, The University of Jordan, Amman 11942, Jordan
8 Chemistry, Department of Chemistry, The University of Jordan, Amman 11942, Jordan
9 Department of Civil Engineering, The University of Jordan, Amman 11942, Jordan
10 Department of Land, Water and Environment, The University of Jordan, Amman 11942, Jordan
11 Department of Geology, The University of Jordan, Amman 11942, Jordan
12 Department of Land, Water and Environment, The University of Jordan, Amman 11942, Jordan
doi
10.22034/gjesm.2026.02.17چکیده
BACKGROUND AND OBJECTIVES: Sedimentation threatens the long-term storage capacity and operational safety of Mosul Dam, one of Iraq’s largest strategic reservoirs. The inflow of sediment from tributary valleys progressively diminishes the effective volume of the reservoir and heightens hydrological risks in the context of fluctuating rainfall patterns. This study aimed to quantify long-term runoff and sediment yield from three major tributaries draining into Mosul Dam and to establish a predictive runoff–sediment relationship to support spatial erosion management.METHODS: The Soil and Water Assessment Tool (SWAT) was applied using climatic, land use, soil, and topographic datasets covering 1985–2024. A gradual manual calibration technique was performed based on the observed runoff and sediment data from Fayda Valley, the only sub-basin in the watershed that has been subject to monitoring. Model performance was evaluated using the Nash–Sutcliffe Efficiency (NSE) as the principal objective function, supported by the coefficient of determination (R²), the index of agreement (IOA), the Root Mean Square Error (RMSE) and the Mean Absolute Error (MAE) and parameter sensitivity analysis was performed to identify dominant hydrological and sediment controls.FINDINGS: The calibrated model achieved good performance (NSE up to 0.94 for runoff and 0.91 for sediment load). Mean annual precipitation was 362 millimeter, characteristic of semi-arid conditions. In the largest sub-watershed, simulated runoff depths reached 91 millimeters, reflecting a notable generation of runoff in relation to the total rainfall amounts in the region. The combined average sediment contribution from the three valleys was approximately 3.8 × 10³ tons per year, with Sweedy Valley accounting for 84 present of total sediment inflow, identifying it as the dominant erosion hotspot. Power-law relationships between annual runoff and sediment yield produced R² values between 0.77 and 0.82, indicating moderate statistical association and confirming nonlinear sediment response to hydrological variability. CONCLUSION: The findings indicate that the sediment transport to Mosul Dam is highly localized and primarily determined by the intensity of runoff. Prioritizing erosion control in Sweedy Valley can substantially reduce sediment inflow and help safeguard reservoir storage capacity. By promoting focused watershed management and minimizing sediment risks, the results directly aid in the protection of water resources as outlined in Sustainable Development Goal 6, as well as enhance climate-adaptive watershed resilience in accordance with sustainable development goal 13.
