Abstract: Helmand River basin (HRB) is the largest river basin in Afghanistan in terms of geographical area while the third in terms of surface water availability after Kabul and Amu River basins. The topography of this basin is characterized by high mountains, plateaus and deserts, which influence the hydrology of the region. Helmand River is the main source of water for irrigation in the basin that plays a critical role in sustaining agriculture and livelihoods in the region.