Flash Floods Hazard Degrees Assessment Applying Multi-Attributes Utility Theory for Gulf of Suez Basins, Egypt

Abstract

Good management of flash floods requires accurate estimation for both the hazard degrees and flood risk maps. Morphological parameters greatly affect the strength of flood’s hydrograph and accordingly the flash flood hazard degree. This study uses decision-making tools such as Multi Criteria Analysis (MCA) and/or Multi-Attribute Utility Theory (MAUT) to estimate the Gulf of Suez’s flash flood hazard degree, Sinai Peninsula, Egypt. The MAUT was applied successfully in estimating the hazard degrees of 56 basins in the coastal zone of the Suez Gulf. Based on the resulted correlation between all hydro-morphological parameters, only six equal weight parameters were selected and used to calculate the hazard degree. The results showed that, about 40 % of the 56 basins have high or moderately high hazard degree. Values of the correlation factors between the hydro-morphological parameters and the resulted hazard degrees are ranged between 0.813 for basin’s Sinuosity and 0.011 for Centroid Stream Slope. The weights of those parameters were non-linearly optimized to make the correlation of all chosen parameters with the hazard degree higher than or equal to the threshold value (0.6). Accordingly, percentage of basins with high or moderately high hazard degree have decreased to 32 %. Capability and validation of current model have been achieved using the damage information of some flood events in the last few decades. The comparison between current model’s scenarios and flood events showed that, all the affected basins that had high or moderated high hazard degree are highly coincide with the real cases.