I just came across a 'green' article discussing the US's largest dam removal project. My first thoughts were that this was just greenwashing putting a slant on this event rather than just talking about the removal as a project addressing an aging piece of infrastructure. But it seems my initial pessimism was wrong.
There are actually two dams to be removed, Elwha and Glines Canyon dams, within the Olympic National Park on the Elwha River. It seems that the sole reason for the removal of these dams is to restore river's catchment.
These two dams were originally built for the purpose of generating hydro-electricity. But it seems that the construction of these resulted in a complete barrier to fish between their upstream and downstream habitats. The main value that will be restored once the dams have been removed is this fish passage.
More information about the dam removal decision can be found at the Elwha Watershed Information Resource website. There are also some cool animations showing how the dams are to be removed at the following websites: Interactive Earth Elwha dam removal and Interactive Earth Glines Canyon dam removal.
The only thing I didn't manage to determine was whether there was another renewable energy source replacing the dams electricity supply (if they were still producing). Hopefully the removal doesn't result in a greater demand for an energy source that isn't environmentally appropriate.