Geomorphological Variables that Determine the Magnitude of Stream Floods in Wadi Al-Hasa - South Jordan

The study aims to analyze the geomorphological variables that determine the magnitude of stream floods in Wadi Al-Hasa through the analysis of the characteristics of rainfall; the shape and areal dimensions of the basin; the topography of the surface; the gradient of the Valley; the characteristics of water discharge network; and the morphology and capacity of the channel. To achieve the objectives of the study, the Analytical Approach was adopted when examining stream floods. This approach is based on the analysis of the climatic information and the hydrological data available on stream floods in Wadi Al-Hasa; and the analysis of the morphometric, hydrological and vegetation measurements that have been extracted from the topographic maps, aerial photographs and field work.

The study found several results including: the increasing likelihood of frequent flooding in the sub-reaches of Wadi Al-Hasa with the increase in their stream orders, as a result of the increase in the amount of water discharge. Moreover, the results of the statistical analysis of the stepwise regression showed the importance of the following variables: (the stream order, the gradient, the width of the river channel and vegetation) in explaining the variation in the volume of the water discharge of the river tributaries in the basin, as these variables interpreted about (53%) of the total variation. The study also found that there are three areas with increased likelihood of flooding in the basin, namely: the estuaries of the eastern tributaries in Qa' Al-Jinz area; the areas where western tributaries meet with higher stream orders; and the estuary area of the mainstream of ??Valley.