Babai

The Babai rises at the eastern end of the Dang valley, where the Mahabharat and Churia hills meet, and flows west along the inner-Tarai trough — an unusual east-to-west course pinned between the two ranges — before turning through the Churia into Bardiya and finally crossing into India's Uttar Pradesh to join the Ghaghara.

It is a modest, strongly seasonal river: the average flow is about 71 m³/s but ranges from a trickle of ≈4 m³/s in April to ≈588 m³/s in July, the classic regime of a hill-fed Tarai river that runs nearly dry just when farmers need it most.

Ecologically it is one of Nepal's richest waterways. The Babai bisects Bardiya National Park, and its valley — emptied of settlement when some 1,500 residents were resettled — has regenerated into prime habitat where rhinos have been translocated, tigers hunt, and gharial and other aquatic life thrive in the river itself.

The Babai is also the receiving end of Nepal's first inter-basin water transfer: the Bheri–Babai Diversion, a National Pride Project, delivers a design flow of 40 m³/s of Bheri water through a 12 km tunnel into the Babai, stabilising irrigation for 51,000 ha in Banke and Bardiya and generating 46.73 MW — transforming the river's dry-season prospects downstream of the hills.