Glen Canyon Dam Might Collapse
Glen Canyon Dam drowned a canyon and changed the river’s ecology. Climate change increases the cycles of extreme droughts and extreme floods, making the dam system vulnerable. Glen Canyon Dam has long been known to be a risk. The most recent flood approaching the observed 100-year average on the Colorado occurred 130 years ago. In 1884, twice the average annual flow of the river passed through Grand Canyon from April to July. The current system has yet to face half of this water volume. When it did in 1983, the spillways at Glen Canyon Dam above Grand Canyon National Park nearly collapsed.
The hydraulic pressure tore through the spillways’ concrete tunnels, eroding the dam from the inside out. Outside, plywood was erected atop the spillway gates to help hold back advancing waters. Nature relented just in time to head off the dam’s failure, and the contents of one of the nation’s largest reservoirs racing unchecked to an equally full Lake Mead and Hoover Dam.