The Global River Widths from Landsat (GRWL) Database contains over 58M measurements of planform river geometry.
“We added up all the rivers and streams around the world [and] got an area larger than the size of Texas. The estimate was significantly larger than the previous best estimate, particularly in the Arctic.”
On the other hand, the researchers estimated that the surface area of rivers and streams in many developed parts of the world was less than expected.
“We think that there is less river water in these areas because humans are modifying the river system,” Allen said. “Water withdrawal and leveeing might be causing rivers to be narrower and more scarce than they would be otherwise.”
Rivers and streams naturally emit significant amounts of greenhouse gasses to the atmosphere. A key factor in estimating the amount of gas released is the amount of surface area occupied by rivers and streams (also called the fluvial network).
“A greater global total surface area implies that rivers and streams contribute more gasses to the atmosphere like carbon dioxide and methane than currently represented by carbon cycling models,” he said.
The GRWL Database already is being used for other purposes such as improving flood models and classifying surface water bodies, including lakes, canals and rivers.
“We think of this database as a first step to a lot more work,” Allen said.
The database will be used as a core dataset for the upcoming NASA Surface Water and Ocean Topography Satellite mission that will measure changes in river and lake water height globally.
The project was funded by NASA.
Media contact: Keith Randall, News & Information, at (979) 845-4644 or firstname.lastname@example.org or George Allen at (530) 902-5024 or email@example.com.