Flood Water Analysis Using LiDAR DEMs Study Area (Sudan - Khartoum- Azozab)

Abstract

Flood is the deadliest type of severe weather. A flood is an overflow of water that submerges land that is usually dry. Floods can also come on quickly or build gradually. It is a well-known fact that the use of Geographic Information Systems (GIS) and Remote Sensing in Water Management is very helpful. This research was conducted in “Azozab”, Khartoum statement, Sudan. Azozab is used to be exposed to severe floods frequently and the last incident of flood was in August 2020. The materials used for this research were Light Detection And Ranging (LiDAR DEM 1, 2020), aerial photograph 2018 with spatial resolution 0.3 m, a polylines shapefile containing flood extent lines in 1946, 1988, an existing protection bank, and field-collected GPS point coordinates. These materials were processed using ArcGIS 10.2 and Archydro to produce a 3-meters vertical interval contour map, 3D coordinates (X, Y, Z) of each of the flood extent lines 1946, 1988, and the existing protection bank, and the drainage system of the study area. The point coordinates of the mentioned lines were plotted as graphs. It was found that the flood line 1946 is 4.59 km long, flood line 1988 is 4.57 km long, and the protection bank is 3.5 km long, therefore, the protection bank should be extended so that its length becomes equal to the length of 1946 flood line, i.e. to be extended by 1.09 Km. Furthremore, the elevations of the protection bank were found lower than the elevations of the higher flood line (1946 ) for a distance of 3.060 km. This distance represents the length of the protection bank that requires increasing its elevations (i.e. the construction of a higher embankment). It was found that the average height increment of the protection bank embankment wall equals 1.37 m approximately. It was found that (11) services such as mosques, education, health and other services are located inside the flood extent line of 1946, thus they were affected by flood. Also, (8) educational services were threatened by flood, because they are located in the vicinity of (i.e. located within 200 meters away from) the 1946 flood extent line.