• Ly Kim Hort
• Eang Khy Eam
• Pen Sytharith
• Doung Ratha
• Chork Vuthy

The Lower Mekong Basin (LMB) hosts a critical transboundary floodplain extending from Prek Kdam and Khsach Kandal in Cambodia to the Vietnamese Mekong Delta. Seasonal inundation in this corridor sustains the region's agricultural productivity and capture fisheries, yet this natural hydrological regime is increasingly challenged by interacting pressures, including upstream hydropower regulation, land use change, and climate variability. These factors intensify flood risks and complicate the governance of shared water resources. To accurately characterize these complex dynamics, this study applies a two-dimensional (2D) hydrodynamic model (HEC-RAS) to simulate the peak flood event of 2022 across the transboundary corridor. The model integrates high-resolution digital terrain data (12m×12m) with observed boundary conditions to capture key hydraulic parameters, including water depth, velocity, and water surface elevation (WSE). Calibration against observed water levels demonstrated strong predictive skill, yielding a Root Mean Square Error (RMSE) of 0.58 m, a Nash–Sutcliffe Efficiency (NSE) of 0.71, and a Percent Bias (PBIAS) of 14.21%. Simulation results highlight pronounced spatial heterogeneity in flood characteristics: deep river channels (5-15 m) exacerbate bank erosion and increase fluvial hazard exposure, while moderate-depth floodplains (1-5 m) support cultivation but are vulnerable to prolonged inundation. Velocity analysis further underscores the dualistic nature of the flood pulse, promoting both beneficial sediment transport and risks of infrastructure damage. The modeling framework developed here provides a robust, high-resolution technical basis for advancing integrated, transboundary water governance, enhancing early warning systems, and informing climate-resilient development strategies across the Lower Mekong Delta.

"Two-Dimensional Hydrodynamic Simulation for Flood Assessment in the Lower Mekong Basin, focusing on the Cambodian Corridor", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.12, Issue 10, page no.b368-b376, October-2025, Available :http://www.jetir.org/papers/JETIR2510152.pdf

"Two-Dimensional Hydrodynamic Simulation for Flood Assessment in the Lower Mekong Basin, focusing on the Cambodian Corridor", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.12, Issue 10, page no. ppb368-b376, October-2025, Available at : http://www.jetir.org/papers/JETIR2510152.pdf