Gandak

Gandak is a transboundary river in South Asia, rising in the Nepalese hills and flowing through Nepal into the Indian state of Bihar, where it joins the Ganges. The river is an important watercourse for both Nepal and India, supporting agriculture, irrigation, and flood management in the region.

Course: The Gandak originates in the mid-hill region of Nepal, traverses the Terai belt, crosses the Nepal-India border, and moves southeast across Bihar before emptying into the Ganges.

Basin and hydrology: The Gandak Drainage Basin covers portions of Nepal and Bihar, with discharge dominated by the southwest monsoon. Seasonal variations produce floods in downstream areas and reduced flow in the dry season.

Infrastructure and governance: A major feature is the Gandak Barrage near Sonpur, which forms part of the Gandak Irrigation Project. Water is diverted into a network of canals supplying irrigation in Bihar. The project is operated under a bilateral agreement between Nepal and India that governs allocation, operation, and maintenance of the river’s resources and associated infrastructure.

Environmental and development notes: The river system faces flood risk, sedimentation, and transboundary water management challenges, which continue to be addressed through cooperation and periodic reviews.

See also: Ganges, Rivers of Nepal, Nepal–India relations.