U.S. researchers say they have scientifically demonstrated the importance of vegetation as a component in river meandering.
Christian Braudrick of the University of California-Berkeley and colleagues built and maintained a scale model of a living meandering gravel-bed river in the lab. They said their findings point to the importance of vegetation to reinforce the banks and in creating sand in healthy meandering river life.
The significance of vegetation for slowing erosion and reinforcing banks has been known for a long time, the researchers said, but their finding marks the first time it has been scientifically demonstrated as a critical component in meandering.
Sand is an ingredient generally avoided in stream restoration since it disrupts salmon spawning. However, the scientists said they showed sand is also indispensable for helping to build point bars and in blocking cut-off channels and chutes — tributaries that might start and detract from the flow and health of a stream.
“The physics and geology of meandering streams combine to yield both shallow portions as well as deeper pools,” Braudrick said. “The diversity of habitat is a more hospitable environment to sustain a higher diversity of species. This is in contrast to another stream type with many islands, but more uniform and shallower water, called “braided streams.”
The research appears in the Proceedings of the National Academy of Science.