The main rivers that flow entirely inside Lebanon are the Litani river (average annual flow of 0.79 million cubic meter), the Ibrahim River (0.51), the Awali River and the Damour River (both 0.3). A large share of the Litani River is diverted through the Markaba tunnel for hydropower generation to the Awali River. Since the upper watershed of the Litani River is polluted and the Awali River is due to be tapped as a source of drinking water supply for Beirut, this water transfer has implications beyond its intended use for hydropower generation.