Keywords: Litani Basin, climate change index, CCI, hydrological modelling, hydro–climatology, climate change scenarios, runoff, Lebanon, climate change impact, surface water, sensitivity analysis, temperature increase, precipitation reduction, climate variations
Sensitivity analysis of climate change impact on the hydrology of the Litani Basin in Lebanon
The effects of climate change on the surface water of the Litani Basin (Lebanon) are examined. A series of 82 hypothetical scenarios are imposed on each of the sub–basins' precipitation and temperature data and an integrated hydrological model is developed while conserving the other climate variables. A sensitivity analysis approach is applied to examine the relative changes of runoff from the historical baseline (1961 to 1999). The analysis suggests that the combination of temperature increase and precipitation reduction produced the largest reduction of the basin's runoff. Furthermore, the climate change water impact index (ICCWI) is developed which detects the degree of the temporal and spatial sensitivity of the basin's runoff to climate modification. ICCWI values indicate that the lower basin is more sensitive to climate changes than the upper basin and that the runoff during transitional and fall seasons is more sensitive to climate variations than during the wet season.