Jordan Journal of Civil Engineering

Dam Breach Risk Analysis and Mapping: A Case Study of the Wala Dam, Jordan

Authors:

Radwan Al-Weshah; Anwar Tarawneh; Murad Alsalahat;

Abstract:

This paper investigates the flood hazard related to dam breach analysis for Wala Dam in Jordan. Hydrologic modeling of Probable Maximum Flood was conducted using the Probable Maximum Precipitation values in the dam watershed. The peak Probable Maximum Flood of Wala Dam watershed was about 2,621 m3/s. Two dam beach scenarios were investigated, namely, overtopping and piping failures using empirical dam breach equations. A 2-Dimensional unsteady hydraulic model was used to route the breach flood downstream of the dam. The maximum peak flows for both the overtopping and piping scenarios were 12,435 m³/s and 5,962 m³/s, respectively. The results are used to generate inundation, flood hazard risk, duration, and velocity maps for areas downstream of the dam. Most inundated areas were classified as extreme hazard areas. The maximum depth of water for overtopping failure is approximately 43 m in some agricultural lands and about 8 m near the Dead Sea Road.  Flooded areas include farmhouses, roads and bridges, the Dead Sea Road and other important public and private properties. Furthermore, the maximum velocities of 17.1 m/s for overtopping case and 15.8 m/s for piping case of failure, respectively. This study demonstrates the importance of developing and regularly updating comprehensive emergency preparedness and enhancing the resilience of downstream communities by community-based disaster risk reduction programs.

Keywords:

Dam Breach, Flood Risk Mapping, Wadi Wala Dam, HEC-RAS Modeling, Flood Hydrology