River restorers can learn a lesson from the beaver that will produce a more natural ecosystem and save money, researchers say. Taking out old man-made mill dams on rivers and streams is a popular practice in New England and certain other states but the restorations are "done with blinders on with regard to the role of the beaver," one researcher said. They argues for maintaining dams in river restorations.
Engineers often start with the idea that rivers are naturally free-flowing, so when it comes to removing dams people built to provide water power for mills, they frequently take out the whole structure. That can involve the costly process of removing all the silt that has built up behind a one-or-two-metre dam since the 19th century. "Many of those streams, before humans built dams on them, were dammed by beavers," they said. "Why not mimic what they do?" That suggests restorers could cut a notch in the dam, releasing the water pressure but not letting the silt flow downstream. The ponds and wetlands that built up behind man-made dams resemble the area behind beaver dams.
This makes sense because there were beaver dams all over NA before the Europeans came. It also seams that it would be a cheaper solution but it also makes environmental sense. Thats a change :). This is a US study but hopefully Canadians are doing the same thing.
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