Groundwater recharge in the Bekaa : insights for enhanced water management

water scarcity, millions of people are subject to insufficient access to safe drinking water and sanitation services in Lebanon. Too often, water scarcity is interpreted as a natural phenomena or the result of technical failures, neglecting the fact that in many cases, water crises are those of socio-political inequalities, poor management and lack of visibility rather than of scarcity. This study attempts to understand the dynamics and the role of recharge due to precipitation in different water level behaviour, using a water balance and water table fluctuation model with field data. Previous researches identify water stress in specific regions such as the Bekaa. This study first reviews Lebanon’s water context before giving the lead to the assessment of the water resources available from previous studies. Then, it gives way to the analysis of water balances that were driven across the Bekaa, in order to improve their understanding with groundwater table data provided by the Swiss Development Cooperation. The development of a conceptual model associated with a thorough literature review enable the assessment of different types of recharge through the Bekaa. A soil moisture water balance, calibrated with actual evapotranspiration data from the WAPOR dataset allowed to compute the recharge due to precipitation process. In a specific aquifer of the Bekaa, the results obtained allowed to validate the previous estimates, with a calibration process leading to a Nash-Sutcliffe coefficient of over 0.89. The water table fluctuation method computes the total net recharge on a specific site, and also allowed to validate previous estimates. Comparing the results of the two methods, it is possible to : validate or refute the conceptual model developed for each zone; eventually identify abnormal recession periods associated with high extraction rates, and give food for thought in the development of an integrated water management at each individual wells given their recharge process. Combining methods of computation of recharge allows to better assess the accuracy of the conceptual model of specific regions of the Bekaa.