Article by Robert Service in this week’s issue of Science
“Over the past 3 decades, increasing concerns about safety and the high cost of upkeep of dams have pushed the number of removals up from an average of about 10 per year to six times that number today, with a total of nearly 1000 dams removed, according to numbers kept by the river advocacy group American Rivers. For much of this time, the focus has been on tearing out small, obsolete structures in the Midwest and East. But that pattern has begun to shift, river restoration experts say; bigger dams are being taken down out west, in part as an effort to rebuild endangered salmon and steelhead runs. Even longtime proponents of dam building, such as officials at the U.S. Bureau of Reclamation, now support removals on a case-by-case basis. All these dam removals have created a unique opportunity for scientists to study how quickly rivers revert to their old ways once obstructions come down.”
