The Impact of the Declining of Rainfall on the Sedimentary Budget of the Libyan Coastal Valleys Stretching from the Mouths of Wadi al-Raml to Wadi Ghanima (North-West of Libya)

Abstract

External drainage valleys constitute the most important main pillars for confronting the imbalance of dynamic balances in coastal areas through the sediments and debris they supply to their outlets, which reduce the erosion and drift of beaches and thus their stability. However, the sediment load of continental valleys depends in turn on several factors, the most important of which are: climate fluctuations in addition to other factors such as geology and topography. The studied area is the Libyan coast extending between the outlets of Wadi Al-Raml and Wadi Ghanima, which is penetrated by several valleys, some of which have managed to reach the sea. They differ in their length and the width of their basins, which is reflected in the amount of water flow and thus in the load and transport of sediments. The research aims to identify the changes that occurred in the environment of the valleys sloping from the eastern part of the Western Mountain and to identify the natural factors affecting them and resulting from the decrease in the amounts of rainwater and its flow in those valleys and the characteristics of their current geomorphological development, as well as to determine their role in the amount and size of their transport of sediments and debris to their outlets and thus the extent of their contribution to the stability of the studied coastline by comparing and analyzing aerial photographs and satellite images taken from Google Earth at different dates and the available geological and topographic maps and digital elevation models (DEM); in order to draw and compare the coastline and produce maps that determine its status in terms of stability or change to understand the current geomorphological dynamics. To achieve the research objectives, the descriptive analytical approach was used and a number of field visits were made to examine the current situation.