Accurate assessments of global river flows and water storage are important to inform water management practices, but current estimates of global river flows represent a significant spread, and river storage Estimates remain sparse. Estimates of river flow and water storage are hampered by uncertainty in land runoff, an unobserved quantity that provides water withdrawal to rivers. In a new study, geoscientists at NASA's Jet Propulsion Laboratory and elsewhere leverage an ensemble of global streamflow observations and land surface models to create a globally gauge-corrected monthly streamflow and storage dataset. Generating. They estimate the average global river storage capacity to be 2,246 km .3 (This is equivalent to half of the water in Lake Michigan, about 0.006% of all fresh water, which itself is equivalent to 2.5% of the Earth's volume) and 37,411 km of the world's continental streams.3 per year.
collins other. Estimates flows through 3 million river segments characterized by intense human water use, including the Colorado River, Amazon River, Orange River, and parts of the Murray-Darling River basin (shown here in gray) identified locations around the world. Image credit: NASA.
Rivers are considered the most renewable, most accessible, and therefore most sustainable sources of fresh water.
Therefore, several studies have attempted to quantify the world's river waters.
However, surprisingly little is known about the average and temporal variation in global river water storage, and even more so, about the temporal variation in global river discharge.
“Over the years, researchers have made numerous estimates of how much water flows from rivers to the ocean, but estimates of how much water rivers collectively hold (known as water storage) “There are fewer and more uncertainties,” said Dr. Cedric David. A researcher at NASA's Jet Propulsion Laboratory.
“We don't know how much water we have in our accounts. Population growth and climate change are further complicating the problem.”
“There are many things we can do to manage our water usage and ensure there is enough water for everyone, but the first question is: How much water do we have? It's the basis of everything else. is.”
In this study, Dr. David and colleagues used a new methodology that combines flow meter measurements with computer models of about 3 million river segments around the world.
They identified the Amazon Basin as the region with the most river water storage, with approximately 850 km of water storage.3 Water amount – approximately 38% of global estimates.
The same basin discharges the most water into the ocean: 6,789 km3 per year. This corresponds to 18% of the emissions into the world's oceans, which average 37,411 km.3 Years from 1980 to 2009.
Although it is impossible for a river to have a negative flow rate, the study's computational approach does not take into account upstream flows, but it is possible that some river segments receive less water than they enter. It may leak.
Researchers found similar findings in parts of the Colorado, Amazon, and Orange river basins, as well as the Murray-Darling basin in southeastern Australia. These negative flows mainly indicate heavy water use by humans.
“These are places where we see evidence of water management,” says Dr. Elissa Collins, a researcher at the University of North Carolina at Chapel Hill.
of study Published in a magazine natural earth science.
_____
Elle Collins other. Global patterns of river water storage dependent on residence time. nut.earth science, published online March 15, 2024. doi: 10.1038/s41561-024-01421-5
Source: www.sci.news
