Why Is This Dam Losing Half Its Water? Modeling Reservoir Sedimentation in Saudi Arabia

This dam was built to hold 20 million cubic meters of water. Today it holds less than half that. In this video we break down a new hydrological model that predicts how sediment builds up behind a dam over time — and how that reshapes a reservoir's elevation-capacity curve (ECC), the relationship between water depth and storage volume that engineers rely on to manage a dam for decades. Using Wadi Fatimah Dam in western Saudi Arabia as a case study, we walk through how the model combines a Sediment Rating Curve (relating storm discharge to sediment load) with an explicit Euler-scheme differential equation to simulate 37 years of sediment accumulation (1985–2022) — without needing dense on-the-ground monitoring data that most arid-region dams simply don't have. We validate the model against a real 2008 ground survey and an independent electrical resistivity survey, and show how it explains roughly 55% capacity loss by 2022. 📄 Read the full open-access paper: Arebu, B.A.; Alamri, N.; Elfeki, A. Hydrological Modeling of Reservoir Sedimentation and Evolution of Elevation–Capacity Curve of the Dam Reservoir. Hydrology 2026, 13, 93. https://doi.org/10.3390/hydrology1303... 🎥 Related videos referenced in this explainer:    • Simulation of Reservoir Sedimentation for ...      • Temporal Evolution of Capacity-Elevation C...   Timestamps (approximate): 00:00 – Why this dam matters 00:20 – The problem: reservoirs silt up 02:00 – Two modeling approaches (and why both fall short here) 04:00 – The Sediment Rating Curve 05:15 – The differential equation model 06:30 – Calibrating with a neighboring gauged basin (Wadi Al-Lith) 07:35 – Calibration results (HEC-HMS, Nash-Sutcliffe) 08:40 – Running the model, 1985–2008 09:25 – Validating against a real 2008 survey + geophysics 10:25 – Limitations 10:55 – Takeaways #Hydrology #DamSedimentation #ReservoirManagement #WaterResources #SaudiArabia #HydrologicalModeling #WadiFatimah #CivilEngineering #ArabianShield #WaterScarcity