New Study Looks at Decline in the Number of Free-flowing Rivers

There has been a major reduction in the number of free-flowing rivers among the planet’s longest rivers. A new study has identified that only a third of the longest rivers still maintain this status. The new research provides important insights because free-flowing rivers play a vital role in the Earth’s ecosystem. The findings are reported in Nature and provide the first global map of river connectivity.


Mapping Out the Earth’s Rivers

To carry out the study, there was a lot of geographical and mathematical work involved. Satellite data of the world’s longest rivers was analyzed. The focus was zeroed in on the 246 rivers that are longer than 1,000 kilometers. The team of experts had to consider 12 million miles of waterways around the globe. The information gained as a result gives some important information about ecosystems and changing patterns in the use of space and resources around the world.

Free-flowing rivers have a very important role to play. These are rivers that are not obstructed along their lengths with human-built structures such as dams and reservoirs. These water bodies help to support the complexity of the Earth’s ecosystems and all the biodiversity that comes along with that. They also play an important role in boosting human social and economic activities. Free-flowing rivers are under threat from various human activities, including all the construction and building work that comes with developing the world’s infrastructure to support a growing urbanized and economic landscape.

The findings reveal that only 37 percent of the longest rivers still flow freely. These are mostly located in more remote areas of the world, including examples in the Congo Basin and the Arctic region in Canada. This means a decline in river connectivity, which is associated with healthy rivers that safeguard the biodiversity of freshwater and transfer sediment to coastal areas. Free-flowing rivers are also very important for fish populations.

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