Dartmouth researchers show how dams and land use are altering flows of sediment.
The way rivers function is significantly affected by how much sediment they transport and where it gets deposited.
River sediment—mostly sand, silt, and clay—plays a critical ecological role, as it provides habitat for organisms downstream and in estuaries. It is also important for human life, resupplying nutrients to agricultural soils in floodplains and buffering the rise in sea levels from climate change by delivering sand to deltas and coastlines.
But these functions are under threat: in the past 40 years, humans have caused unprecedented, consequential changes to river sediment transport, according to a new Dartmouth study published in Science.
Using satellite images from the joint NASA/United States Geological Survey Landsat program and digital archives of hydrologic data, Dartmouth researchers examined changes in how much sediment was carried to the oceans by 414 of the world’s largest rivers from 1984 to 2020.
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