Recently, the impacts of the growing population in Lebanon have placed tremendous stress on water resources, especially groundwater. Tripoli Aquifer, which is located at Lebanon's northern coast and has an unconfined hydraulic nature, is subjected to salinization due to excessive water withdrawals. This study aimed to construct a groundwater transport numerical model (Modflow) in order to investigate the salinity dynamics behavior where the pumping wells are located, and to predict the situation over the coming 20 years. The developed model is successfully calibrated against measured field data. Results reveal the augmentation of aquifer water salinity and the significant role of Nahr AlBared River in recharging the aquifer with freshwater. It could supply the nearby wells (Al Rabie wells group) with sufficient fresh water while other wells are significantly subjected to salinization which may be reduced by about 50% through adding a shoreline barrier.