Application of Numerical Hydrodynamic Modeling for Flood Mapping and Simulation of the Euphrates River

Flood risk along the Euphrates River downstream of Haditha Dam has become a critical concern due to increasing hydrological variability and the growing impact of climate change on extreme flow events.This study presents an integrated numerical modeling approach using Hydrologic Engineering Center-River Analysis System (HEC-RAS) and Hydrologic Engineering Center-Geographic River Analysis System (HEC-GeoRAS) for generating flood inundation maps along the river reach downstream of the dam.A calibrated and validated hydrodynamic model was developed to simulate river flow under different discharge scenarios corresponding to return periods of 50 and 100 years.The model outputs were coupled with Geographic Information Systems (GIS) to delineate flood extents and identify high-risk zones.The finding indicates that extensive regions along the river corridor are vulnerable to inundation under extreme discharge flow conditions.Flood maps revealed spatial variations in hazard levels, highlighting critical (highly susceptible areas) where inundation depth and extent pose significant risks to nearby communities and infrastructure.The simulations for 50-and 100-year return period discharges demons trate a substantial increase in floodplain coverage, emphasizing the potential for severe flood events.Furthermore, the study confirms that the integration of numerical hydrodynamic models with GIS tools provides a powerful framework for visualizing and assessing flood hazards.This approach enhances the ability of decisionmakers to develop effective emergency response plans, optimize flood management strategies, and support sustainable river basin management.The results underscore the urgent need for proactive planning and risk mitigation measures in the Euphrates basin, particularly under evolving climate conditions that are likely to intensify extreme hydrological events.Unsteady flow modeling compare to steady flow modeling, offers more information on the dynamics of the flood waves, especially the propagation of the wave along the river.The result show the inundation damaged area can include 186124 Donum.