Rivers are critical resources that affect everything from watersheds to agriculture to energy. But rivers, in turn, have been impacted by humans, often in the form of hydraulic infrastructure such as dams and wells.

A new project, led by Stefano Galelli, associate professor of civil and environmental engineering in the Cornell Duffield College of Engineering, will create a global record that shows how river systems around the world have changed under human influence over the last 75 years.

The project, Dynamic Atlas of Riverine Ecosystems and infrastructure (DARE), received a $5 million grant from Schmidt Sciences as part of the foundation’s Virtual Institute for Earth’s Water (VIEW) program, which aims to create a definitive account of the planet’s freshwater resources.

By using satellite data and computational modeling, the five-year project will track changes in river discharge, sediment transport, temperature and fish biodiversity in all the world’s rivers from 1950 to 2025.

The resulting atlas will pinpoint what changes have occurred, when and where, and who or what is driving them. It will also quantify the ecological consequences. 

“Essentially, this a global product that provides high spatio-temporal resolution reanalysis of river discharge, along with key bio-physical processes like water temperature, sediment and fish biodiversity,” Galelli said.

Galelli’s team includes co-PI Alexander Flecker, professor of ecology and evolutionary biology in the College of Agriculture and Life Sciences, and collaborator Carla P. Gomes, the Ronald and Antonia Nielsen Professor in the Cornell Ann S. Bowers College of Computing and Information Science. The team also includes researchers from University of Maryland; University of California, Santa Barbara; World Wildlife Fund (WWF); Tufts University; McGill University; West Virginia University; Indiana University; Stockholm Water Institute; Asian Institute of Technology; and Universidade Federal de Rondônia. Of the four teams selected for the VIEW program, DARE is the only one based in North America.

The team will combine techniques in hydrology, ecology, remote sensing and computational modeling. The project’s first stage is to develop a global hydrologic model that simulates the relationship between climate, humans and rivers since 1950 while accounting for changes in water management practices, with an acceptable level of uncertainty. 

“You cannot do a perfect mathematical model of a river, and definitely there is uncertainty in a lot of factors, like how the upstream dams were operating, or which type of crop did they use in 1975. That will definitely influence how much they irrigated, and therefore how much water you have in a river,” Galelli said. 

The researchers plan to study the Amazon and Mekong rivers to fine-tune their model and ensure they are accurately capturing the river processes. WWF researchers will also work with local stakeholders and policymakers to get a sense of how the atlas can be used to guide river restoration efforts.

“Rivers are silent providers of natural resources. When we talk about ecological and ecosystem services, there’s a lot that rivers do that we don’t even realize,” Galelli said. “But we don’t have globally coherent datasets on how we have impacted rivers. And if we don’t have that, we don’t know how to restore them or how to plan for the future.”