The Gandaki river basin is a transboundary basin lying north-south in the central Himalayan region. It extends from China in the north, through Nepal, to India in the south and is bounded by the Karnali basin to the west and the Koshi basin to the east (Figure 1). The basin has a total drainage area of 46,300 km2 – 72% in Nepal, 18% in India, and 10% in China – and includes part of Xiagaze prefecture in Tibet Autonomous Region in China, 19 districts in Nepal (12 entirely and 7 partially within the basin), and 9 districts in India. The Gandaki river is known as the Narayani in the plains of Nepal and as the Gandak in India, where it joins the Ganges (Ganga) at Hajipur near Patna. It has seven major tributaries (the Kali Gandaki, Seti Gandaki, Madi, Marsyangdi, Daraudi, Budhi Gandaki, and Trishuli), of which all except the Daraudi and Madi have catchment areas with glaciers (Bajracharya and Shrestha 2011). There are 1,710 glaciers in the upstream catchments (as of 2005), with an area of 2,285 km2 and estimated ice reserves of 194 km3 (Bajracharya and Shrestha 2011: 56). Many smaller rivers and rivulets also drain into the Gandaki including, for example, the east Rapti river, which joins the river at Chitwan.
