Hydrological Impact Simulations of Climate Change on Lebanese Coastal Rivers

Hydrological impact simulations of climate change on Lebanese coastal rivers are investigated. The impacts of the precipitation scenarios on streamflow and annual runoff coefficient are rather moderate. The relative decrease in flow is greater due to the low value of the runoff coefficient of the catchment. It is suggested that the impact on the water cycle is related to the effect of a temperature increase on the seasonal snow cover. It is observed that with a 2 degree C increase; the modifications of streamflow regimes are significant. Shortage periods are earlier by 15 days to one month and rainfall floods often replace snowmelt floods. This disturbs the hydrological regimes of the rivers such as Nahr Ibrahim and yields important water management problems.