South Carolina Dam Failures Point to Need for Emergency Action Plans

This map provided by the state of South Carolina shows the large number of roads and bridges closed across the state as of Monday, October 12.

Lives lost. Houses under water. Roads and bridges washed away. Dams failing.

The images and stories coming out of South Carolina over the continuing catastrophe have been horrific and heart-wrenching.

We are hearing a lot about thousand-year rains and hundred-year floods in parts of South Carolina.

Ellen Faulkner, an Ayres Associates water resources engineer who has spent much of her 25-plus-year career studying dams and dam failures, said dams are typically designed to survive floods with annual probabilities between 1% (the hundred-year flood) and something much rarer (the probable maximum flood).

“But no matter what the structure is designed for, a flood this big tests all kinds of systems in ways they have never been tested before,” Faulkner said. “It’s not just the engineering. Communication doesn’t work, power is lost, access is cut off, floating debris hinders operations, and the dam owner’s staff and emergency managers are overwhelmed by other responsibilities.”

That’s why, Faulkner said, almost every dam, no matter how rigorously designed, has an Emergency Action Plan (EAP) for the event of a dam failure. “Responsible dam owners, designers, and regulators understand that no dam is fail-proof and plan accordingly,” she said. The Willow River State Park Little Falls Dam Inspection is an example of a project in which Ayres provided an EAP.

Dustin Robinson, a water resources engineer in Ayres’ Fort Collins office, said his group has been following the flooding with close interest, having worked on bridge projects in South Carolina. The Fort Collins staff has firsthand experience with flooding recovery projects after heavy rains caused massive flooding two years ago in central and northern Colorado.

“During the Colorado flooding we were driving around Loveland and Fort Collins documenting the flooding and checking on bridges, erosion, roadways, etc.,” Robinson said. “After the flooding peaked and started to recede, we had several roles in helping assess and repair damages.”

He said the effects of major flooding can last a long time. “We will likely be working on flood recovery projects for another five years,” he said.

For a look at nine pictures South Carolina flood victims want you to see – showing bravery, heartache, and neighbors helping neighbors – see this blog post from the Weather Channel.

If you would like to inquire about Emergency Action Plans, post-flood dam inspections, or other dam design and maintenance issues, contact our water resources group.

Ayres Associates engineers were called into action in 2013 when flash flooding hit near our Fort Collins office in Colorado.