Locating flood susceptible areas in Sabah Al-Ahmed city, Kuwait

Abstract

In Kuwait, about 111 ​mm of heavy rainfall occurred overnight in 6 ​hours on the 6th of November, 2018, caused flash floods in several areas. This study deals with the preparation of flood risk maps for Sabah Al Ahmed city by using the digital elevation model (DEM) and geographic information system (GIS) tools. Secondly, the detection of areas at risk from flash floods was done using the hydrological method. Using hydrological methods of GIS tools, the present work started with fill, flow direction, flow accumulation, basin, stream link, stream order, and stream density. In addition, quantitative descriptions of watershed morphology were used, such as the length/width ratio which was 2.64, indicating that the watershed was slightly rounded. The form factor was calculated at 0.37, indicating an inconsistent shape. The relief ratio was 0.03, indicating it was low relief. As a result, the most detected channels were the seventh, sixth, and fifth stream orders. In addition, the stream morphological equations yielded a texture ratio of 48.6 ​km, indicating a smooth texture. The bifurcation ratio was 3.12, indicating that the surface runoff had a high velocity. Also, the drainage density was 3.7 ​km/km2, and the stream frequency was 7.2 streams/km2. The watershed had moderate texture. Finally, the flood risk map showed that the study area was a very high-risk area with 1.1% of the watershed. The GIS was used in a flood risk analysis due to the potential risk it posed on people, buildings, and infrastructure in the affected areas.