Hydromorphometric study of the flashflood occurred on the 1st of November 2020 in Ras Gharib City– Egypt

The city of Ras Gharib and its surroundings have recently been subjected to repeated sudden flashfloods that led to the closure of the coastal road and disrupted the main transports to and from the Red Sea Governorate. Of which, flashflood of 26 and 27 October 2016 is mostly the worst in the last 50 years, as it killed dozens of people and destroyed the infrastructure and property. The city was also recently exposed on 01^st November 2020 to another similar flashflood, but less severe than that of 2016.
This research aims to reveal the hydromorphometric properties of the flashflood occurred on the first of November 2020, to estimate rain water and losses volumes, the net volume of runoff in the wadis that cross the main coastal roads in the Ras Gharib region, ways to benefit from rain water and reduce the damage of frequent flashfloods. A number of advanced methods have been used, including morphometric analysis and the extraction of drainage networks and wadis from DEM, Landsat images and images from Google Earth Pro with high spatial resolution, and the analysis of rain data obtained from the PERSIANN-CDR and PERSIANN-CCS models to estimate rain volume and the calculation of losses by evaporation-transpiration as well as by infiltration into the soil, using GIS and remote sensing techniques.
The study concluded that the wadis of the study area received approximately two millions m³ in wadi Abu Haad, and 1.3 million m³ in wadi al-Darb. The total losses amounted to about 729,814.4 m³ in wadi Abu Haad, and 911,407.4 m³ in wadi al-Darb. The net runoff was estimated as 1,390,182.92 m³ in wadi Abu Haad, with a rate of 65.57 % of rain volume that fell on the wadi, and 428,893.73 m³ in wadi Al-Darb, or 31.99 % of the rain volume that the wadi received.