Balancing Hydropower and Freshwater Environments in the Global South

Hydropower generation is growing rapidly in the developing tropics. To this end, dams are and will be constructed at a fast pace in the coming decades, with the vast majority of new dams expected to be built in the Southern Hemisphere and Asia. Freshwater ecosystems, which have already suffered intense deterioration in recent decades – the Living Planet Index indicates an 89% loss in biodiversity in these – are tremendously vulnerable to dam-induced ecological change. Dams modify river water and sediment regimes with often negative consequences on ecosystem services, wetland conservation, water quality, land fertility, and fisheries productivity. Dam and reservoir construction may also lead to increases in green-house gases emissions, leading to an exacerbation, rather than mitigation of climate change. Until recently, the majority of research on dams and freshwater ecosystems has focused on the Northern hemisphere, while coming impacts will occur heavily in the Global South.

In spite of its known social and ecological impacts, hydropower is generally considered a fairly cheap and a relatively environmentally friendly source of energy. Dams for energy generation also provide water for irrigation and urban water supply. The pressing need for more energy to sustain economic growth and the increase in per capita use of power is fueling continued dams’ construction. However, these benefits come at the expense of other ecosystem services provided by free-flowing rivers. To advance our understanding of these trade-offs and strike a balance between hydropower and other freshwater ecosystems benefits, key questions related to the social and economic values of both have to be answered. What will be gained? What will be lost? In what time frame? Who will win? Who will lose? Old instruments to answer these questions need to be used in novel ways. New and better-performing tools and methods are necessary.

The aim of this Research Topic is to highlight promising and urgently needed research aiming to answer the recurring question of hydropower vs freshwater balance, as well as developing novel tools to do so. Areas to be covered in this Research Topic may include, but are not limited to, the following topics:
• Trade-offs between hydropower and other freshwater benefits;
• Hydropower and climate change;
• Reservoirs effects on sediments and nutrients transport and balance;
• Small dams and high frequency modifications of hydrologic regime. Are there any significant impacts?
• Cumulative effects of reservoirs at the basin scale. What about basin planning?
• Solutions to basin-wide erosion and deposition;
• Assessment of alternatives to hydropower;
• Hydropower and social conflicts;
• Innovations in hydropower mitigation techniques; and
• Lessons learned from hydropower.

We welcome Original Research, Review and Perspective article types.