Flash floods are among the mostcommon natural hazards in Egyptian andArabian deserts. In this work, we utilized two Sentinel-
1 and Sentinel-2 satellite images, before and after the flash flood, SRTM, and geolocated terrestrial photos captured by volunteers.
Tis paper aims to three substantial objectives: (1) monitoring the flash flood impacts on Wadi El-Natrun region based on free
satellitedataandmappingthedestroyedvegetationcover;(2) theintegrationofthefreeremotesensingdata,geolocatedterrestrial
photos, and GIS techniques, along with hydrologic and hydraulic modeling, to evaluate the impact of flash flood hazards on the
study area; and (3) assistance of the decision-makers in planning the required protective works to avoid the probable flooding.
Two scenarios have been applied to estimate the flash flood effect. Te first scenario has relied on Sentinel-1/2 data fusion before
and after the flash flood, while the second scenario has been implemented based on the integration of the Sentinel-2 images and
hydrologic and hydraulic flood modeling with the help of ArcGIS software to simulate the flash flood route. Te results
demonstrated that although the first scenario is an efficient solution for continuous monitoring of the change in the water bodies,
it is limited in the detection of the submerged vegetation area. On the other hand, the second scenario provided the flash flood
route and hydrological parameters, which determine the hazard degree of the basins, thus helping the decision-maker to manage
the flood risk. Moreover, the second scenario surpasses the first one by estimating the destroyed infrastructure. Consequently, the
second scenario is appropriate to assess the flash flood impacts and mitigate its influence in the future. |
