Dams were a popular way (and still are in some places) to manipulate water reserves for people and as a way to generate energy. The problem with this naturally flowing water being dammed is that it kills fish and negatively impacts other wildlife. Dams cause a huge amount of damage on their local ecosystem and this cascades to more damage with each additional flow blockage.
It’s time to teardown the dams.
There are other reasons to reconsider dams: many of them, like our roads and bridges, are aging. The US Army Corps of engineers estimates that a third of the dams it monitors pose a “high” or “significant” hazard. The same week I traveled to Yosemite, severe rain in South Carolina washed out 14 dams and weakened 62 others. Nineteen people died. It was a grim reminder that some of our dams are already coming down, without our help.
Over the last two decades, organizations like the Sierra Club and American Rivers have spearheaded a movement to remove nuisance dams. Their campaign has been remarkably successful: between 2006 and 2014, over 500 dams were removed from American rivers — more than were taken down over the entire century prior.