Rethinking reservoir operations: how expanding operation goals can yield win-win climate adaptation outcomes

Economic development, population growth, and climate change have triggered an increase in global dam construction as a source of domestic water supply, irrigation, and renewable energy. The economic benefits associated with dams have historically been the primary drivers in decisions about how to operate reservoirs. However, this approach often benefits private companies and governments while placing the costs of hydropower development on local communities and the environment, resulting in steep social and ecological consequences. Maximizing the economic benefits of water releases from reservoirs disrupts natural flow regimes, which can fragment free-flowing rivers, severely alter or destroy aquatic ecosystems, restrict access to water resources, cause transboundary conflicts, and modify water quality. Climate change is only projected to exacerbate these multisectoral conflicts in the future, increasing the intensity and frequency of hydrologic extremes in river basins around the world. However, these tensions will deepen in absence of infrastructure development as well. In understanding the vulnerability of reservoir systems to climate change, it is important to consider whether the infrastructure is mitigating or exacerbating those impacts. In this study we rethink how reservoirs are operated and investigate whether robust and adaptive reservoir management can actually reduce socioecological conflicts under climate change relative to uncontrolled conditions. As a case study for our analysis, we consider the Omo River basin of Ethiopia, where controversial dam construction is creating opportunities for hydropower and irrigation but has proven detrimental to indigenous people and aquatic wildlife dependent on the natural flow regime. Leveraging advancements made to the Soil and Water Assessment Tool’s reservoir module, we find that smart reservoir operating policies can improve climate resilience to extreme flow events while balancing economic, agricultural, social, and ecological outcomes. While these operating policies exhibit tradeoffs between preserving the distribution of historical high versus low flows, we also identify compromise solutions that yield win-win climate adaptation outcomes, showing the multi-sectoral benefits of smart infrastructure development.