There are roughly 80,000 dams in the U.S., only 3 percent of which now generate electricity. . . . The pace of removal has quickened, with 241 dams demolished between 2006 and 2010, more than a 40 percent increase over the previous five years.Of course, just because a dam doesn't generate electricity doesn't mean it does nothing. Some dams have created huge lakes that have become the centers of resort communities, like Deep Creek Lake in western Maryland. And others create reservoirs for water supply. But many are doing pretty much nothing, except for sitting picturesquely next to the ruined grist and paper mills they used to supply with power. Above, the 2007 demolition of the Marmot Dam on the Sandy River in Oregon. This made the Sandy River a free-flowing river from Mount Hood glaciers to its mouth at the Columbia River for the first time in 95 years.
Removal of the Ballou Dam from Yokum Creek in Massachusetts. I suppose the optimistic way to see this would be that after 5000 years of altering nature as much as we could, we have become more sensitive to our impact and more interested in preserving natural systems like free-flowing rivers. I would be more likely to see things that way if we weren't burning such a gigantic quantity of fossil fuel. Dam removals done so far have honestly had a tiny impact on our ability to generate power, but taking hydroelectric power off the list of potential alternatives only increases our dependence on coal and gas.