Beavers don't read engineering manuals, but it turns out their dams can do something engineers spend millions trying to achieve: slow down floodwater. A new U.S. Geological Survey study looked closely at two small urban creeks near Portland, Oregon, and found that beaver dams slowed down a significantly higher amount of water flow during storms than the same creeks but without dams. This did not stop the floods, but it certainly bought enough time to cope with the problem. For cities around the world fighting flash floods, that detail matters.
So what did the scientists actually study?
