The general circulation models (GCMs) projections of the Intergovernmental Panel on Climate Change (IPCC) indicate an increasing temperature and a drying trend in the Middle East and North African (MENA) region by the end of the 21st century. Accordingly, Lebanon’s water resources are expected to be heavily affected, and concomitantly, urban water demand is expected to increase. In this context, this thesis focuses on the impact of climate change on water demand in Greater Beirut Area (GBA) and the water flow in El Kalb basin – which feeds 70% of GBA population. This study is the first to: (1) ...