Accurate assessment of global river flows and stores is critical for informing water management practices, but current estimates of global river flows exhibit substantial spread and estimates of river stores remain sparse. Estimates of river flows and stores are hampered by uncertainties in land runoff, an unobserved quantity that provides water input to rivers. In their new research, geoscientists from NASA’s Jet Propulsion Laboratory and elsewhere leverage global river flow observations and an ensemble of land surface models to generate a globally gauge-corrected monthly river flow and storage dataset. They estimate a global river storage mean of 2,246 km3 (that’s equivalent to half of Lake Michigan’s water and about 0.006% of all fresh water, which itself is 2.5% of the global volume) and a global continental flow of 37,411 km3 per year.
Rivers are considered the most renewable, most accessible and, hence, most sustainable source of freshwater.
Accordingly, several studies have sought to quantify the water in our world’s rivers.
Yet, surprisingly little is known about the average and temporal variability of global river water storage, as well as the temporal variability of global river flows.
“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 Dr. Cédric David, a researcher at NASA’s Jet Propulsion Laboratory.
“We don’t know how much water is in the account, and population growth and climate change are further complicating matters.”
“There are many things we can do to manage how we’re using it and make sure there is enough water for everyone, but the first question is: How much water is there? That’s fundamental to everything else.”
For the study, Dr. David and colleagues used a novel methodology that combines stream-gauge measurements with…
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