Water-energy-food nexus in the Yarlung Tsangpo-Brahmaputra River Basin: Impact of mainstream hydropower development

Abstract

Study region: Yarlung Tsangpo-Brahmaputra River Basin Study focus: A large-scale hydropower system with reservoir storage on a transboundary river brings both opportunities and challenges to water, food, and energy securities of the riparian countries. This is the case for the possible cascade hydropower system in the Great Canyon of Yarlung Tsangpo. From the perspective of Water-Energy-Food (WEF) nexus, this study analyzed the possible trade-offs and synergies among hydropower production, waterway navigation and agricultural irrigation. With streamflow simulated by the THREW distributed Hydrological model, multiple-objective optimization has been performed by the WEF nexus model which is aiming at revealing the potential for transboundary cooperation on enhancing basin-wide benefits. New hydrological insights for the region: Apart from bringing 33.7∼75.0 % more hydropower productivity for each month, the reservoir storage of YB River mainstream hydropower system can also increase the minimum flow during dry season, extending the period with navigability by one to four months per year from the Majuli Island to downstream. It provides higher assurance rate of irrigation water requirement in Bangladesh, effectively mitigating flood damage by reducing downstream flood-affected area in India and Bangladesh by up to 32.56 % and 14.8 % respectively. The possible mainstream hydropower development can contribute significantly to basin-wide benefits through transboundary cooperation in the YB River basin.

Keywords

• Yarlung Tsangpo
• Brahmaputra
• Water-Energy-Food nexus
• Scenario analysis
• Hydropower
• Flood control