The State of Flow: A Brief Exploration of Man-made Dams in the United States
I’ll be the first to admit that my knowledge of dams is pretty limited. I know that thousands of them exist in the United States, that they generate hydropower, and that they have a negative effect on the surrounding population of native wildlife. Other than that, I have a lot to learn. So when a documentary film about American dams was released earlier this year, I was excited to check it out.
The film, DamNation, made its debut on Netflix (and in my living room) a couple weeks ago and opened my eyes to the extensive damage that dams have caused in our country over the past century. Potentially the most well-known negative effect of dams is the fact that they block the movement of fish. This has a significant impact on the reproduction of native species, as many fish migrate from oceans to rivers to spawn. Dams also transform free-flowing rivers into lake-like habitats, meaning the fish and other native wildlife that thrive in river habitats do not fare well. In addition to the degradation of native species, dams negatively affect water quality and impede river-based recreation.
So, why then, were so many dams constructed in the first place? The majority of dams in the United States were built in the early 20th century before we had a strong understanding of the ecology of rivers. They also predated the Clean Water Act, Endangered Species Act, and other environmental laws. While hydropower probably seemed like a great source of renewable energy at the time, recent studies have estimated that more than 20% of all man-made methane emissions come from hydropower reservoirs. Here’s an interesting way to wrap your head around that number – imagine 6,000 cows being flatulent for one year. That’s the amount of methane that was produced from a single dam-made hydropower reservoir in Ohio in 2012. Wow!
Awareness of the overwhelmingly negative impacts of dams has dramatically increased over the past couple decades, sparking dam removal projects across the United States and the world. The largest dam removal project to date was completed in August on the Elwha River in northwest Washington. The river now flows freely and the ecosystem is recovering more quickly than many imagined. Next summer, participants of Hante Pacific Northwest will witness the healing of the Elwha River firsthand as they visit the former site of the dam. They’ll have the opportunity to explore the once-altered landscape and develop their own opinions regarding dams and dam removal.
If you’d like more information about the Elwha Dam removal project, read this article in Newsweek. Want an interactive demonstration of the effects that dams have on rivers? Check out this fantastic website: http://www.dameffects.org/index.html.