The novel approach to estimating river water storage and discharge also identifies regions marked by ‘fingerprints’ of intense water use.
A study led by
Challenges in Estimating River Storage
Although researchers have made numerous estimates over the years of how much water flows from rivers into the ocean, estimates of the volume of water rivers collectively hold — known as storage — have been few and more uncertain, said
Although it’s not possible for a river to have negative discharge — the study’s approach doesn’t allow for upstream flow — for the sake of accounting, it is possible for less water to come out of some river segments than went in. That’s what the researchers found for parts of the Colorado, Amazon, and Orange river basins, as well as the Murray-Darling basin in southeastern Australia. These negative flows mostly indicate intense human water use.
“These are locations where we’re seeing fingerprints of water management,” said lead author Elyssa Collins, who conducted the analysis as a JPL intern and doctoral student at NASA’s Shuttle Radar Topography Mission. This approach yielded discharge rates, which were used to estimate average and monthly storage for individual rivers and the planet’s rivers in total.
Using a consistent methodology enables comparisons in flow and human drawdown between different regions.
“That way we can see where in the world the most amount of river water is stored, or where the most amount of water is being emptied into oceans from rivers,” said Collins, now a postdoctoral researcher at the University of North Carolina at Chapel Hill.
Reference: “Global patterns in river water storage dependent on residence time” by Elyssa L. Collins, Cédric H. David, Ryan Riggs, George H. Allen, Tamlin M. Pavelsky, Peirong Lin, Ming Pan, Dai Yamazaki, Ross K. Meentemeyer and Georgina M. Sanchez, 22 April 2024, Nature Geoscience.
DOI: 10.1038/s41561-024-01421-5