“NEWBURGH, N.Y. — For thousands of years, alewives and blueback herring have left the ocean to swim up the Hudson River to any one of scores of tributaries to lay their eggs. But in a more recent era, the fish have been literally hitting a wall as dams popped up all over the region, powering grist and woolen mills and later factories.
Today, there are an estimated 2,000 dams in the Hudson River Estuary between New York City and Albany, N.Y. Many are small and obsolete, abandoned by long-shuttered factories and serving no purpose other than to thwart fish migration and harm river ecology.
Now a growing band of environmentalists wants to restore the waters to their natural state. They are targeting dams for removal not only in the Hudson Valley but across New York and the United States.
“Small dams are everywhere, and many of them just persist through inertia,” said John Waldman, a biology professor at Queens College and the author of “Running Silver: Restoring Atlantic Rivers and Their Great Fish Migrations.” “Until recently, no one had the wherewithal or energy to take these things down.” “