There are more than 260 transboundary river basins in the world which cover nearly half of the Earth’s surface. These rivers, traversing around 145 countries, are a common cause of conflict between nations. The case study selected for this study is the Teesta River, a tributary to the Brahmaputra which flows from India to Bangladesh, where water sharing between India and Bangladesh has a long and disputed history. The model quantifies economic net benefit of opportunities to share water between the countries using a Hydro-Economic Model (HEM).
Whilst HEMs exist for many transboundary river basins including the Nile Basin, the Ganges Basin, the Mekong, Volta, and Amu Darya, most HEMs that treat transboundary water issues consider a limited scope of water values most frequently including: agriculture, hydropower, and municipal water uses. However, water has many additional values including navigation, environment, fisheries, and water quality. This study adds to the HEM literature by considering a wider range of benefits than have commonly been included in HEM assessments of transboundary water sharing in the past. Results show that a re-allocation scenario with more water flowing over the border from India to Bangladesh leads to an overall annual basin-wide gain. The estimated loss for India (mostly lost hydropower value) would be substantially greater if non-extractive flow related benefits for fisheries, navigation, sediment transport and environment were not accounted for. Similarly, estimated gain for Bangladesh would be much less if these non-extractive flow related benefits were ignored.