Implementation of Remote Sensing and GIS Techniques to Study the Flash Flood Risk in Tanezzuft Valley, Libya.

Abstract

The Tanezzuft valley is located in the Southwest of Libya, and due to its fascinating location between Acacus - Tassili scraps, and sub-Saharan and northern regions, it is considered one of the largest and most important valley in the region.The valley is characterized by the extension of its basin from south to north for a distance of approximately 185 km, and many important parts of its drainage basins are located within Algerian territory. On this valley, there are a number of cities and villages including Al- Barakat, Thala, Al-Fuwait, and Ghat, which were exposed to a heavy rain and flash flood in June 2019, resulting in the destruction of many houses, roads, farms, and the displacement of thousands of citizens.This paper discussed the role of geographic information systems (GIS) techniques and tools in understanding the geomorphology of the valley especially in which Ghat is located, the risks of rain and flash flooding in the region, and proposed some technical solutions to mitigate the influence of the flood. The GIS analysis revealed that watersheds (3,4,5) have the main impact on the water surface and flooding in the valley, and all the modern cities are located at the lowest elevation inside the valley. The techniques helped to define proposed dam locations as well as to propose the geographical location of the destructive dams at some wadi streams. The study's findings and the final maps can be used to develop some solutions to reduce flood risks in the study area, such as the establishment of dam plans to reduce torrent flow, as well as the preparation of an urban plan for the area to avoid areas of rainwater flow and flash floods.