Nonprofit, nonpartisan journalism. Supported by readers.


Meandering through the lab

The meandering stream is a fixture in our natural landscape.

The meandering stream is a fixture in our natural landscape. But scientists seeking to restore rivers and wild-life habitat have struggled to recreate in labs the water flow, sediment and bank conditions that can steer a stream through twists and turns. Man-made models and restored meanders have insisted on straightening out or else branching into multiple streams over time.

Building on alfalfa-sprout studies at the University of Minnesota, which is headquarters of the National Center for Earth-Surface Dynamics, scientists at the University of California, Berkeley, have created the first experimental meanders in a flume — a scaled-down representation of a natural channel. The findings are reported in the Proceedings of the National Academy of Sciences.

It turns out that the roots of the alfalfa sprouts provide strength to the soil and protect the banks from the force of the water so they don’t wash away.

The Berkeley scientists say such flume models can help direct spending for stream restoration: “The money spent nationally on stream restoration is expanding exponentially, yet we’re fixing things faster than we can tell whether it’s doing any good,” said UC Berkeley graduate student Christian Braudrick, a former environmental consultant.