Why the World’s Rivers Are Losing Sediment and Why It Matters
Vegetation is returning to this Elwha River valley in Washington state after two dams were removed. OLYMPIC NATIONAL PARK/FLICKR
Why the World’s Rivers Are Losing Sediment and Why It Matters
Vast amounts of river-borne sediment are trapped behind the world’s large dams, depriving areas downstream of material that is badly needed to build up the marshes and wetlands that act as a buffer against rising seas.
By Jim Robbins