Dams fail. It’s inevitable and it’s happening now.
Flooding of the Waccamaw River at Pitch Landing SC thanks to Hurricane Matthew. | Laila Johnston
Flooding of the Waccamaw River at Pitch Landing, SC thanks to Hurricane Matthew. | Laila Johnston
Just recently, Hurricane Matthew caused widespread flooding and more than 20 dam failures in North and South Carolina.
Rewind one year to October 2015— same place, different storm. One out of every 50 dams regulated by the State of South Carolina failed (plus hundreds of unregulated dams). This was the second most costly environmental disaster in South Carolina’s history — $12 billion. And more devastating than the financial cost is the loss of life (so far 59 people in the U.S. between the two storms) and destruction of homes and businesses (more than 1 million structures destroyed in Hurricane Matthew).
Fast forward to early October 2016, thousands of people have been evacuated from their homes due to the threat of dam failures in North Carolina. Plugging a hole the size of a truck will require more than a little duct tape.
Part of the problem is that we aren’t thinking ahead. Many dams look very formidable. Big walls. Strong. But concrete breaks down over time, especially when subject to the forces of nature. So does brick and mortar. And earthen dams? No doubt.
We need a commonsense approach to managing our infrastructure.
WHY DO DAMS FAIL?
Penobscot River | PRRT
Veazie Dam breach on the Penobscot River, ME
Dam failure can result from any number of issues, including: inadequate spillway design, spillways blocked by debris causing dam overtopping, land use change causing increased runoff, outdated technology and design, changing weather patterns that alter flow rates, defects in the dam’s foundation, settlement of the dam crest, internal erosion of the dam caused by seepage (this can happen around pipes, animal burrows, plant roots, other cracks), structural failure of the materials used in dam construction, and/or inadequate maintenance of the structure.
Dams are deteriorating faster than they can be repaired. According to the Association of State Dam Safety Officials, the cost to rehabilitate our nation’s dams would be more than $70 billion (high hazard dams alone would cost $18.2 billion to rehabilitate).
[clickToTweet tweet=”According to @Dam_Safety, it’d take $51 billion to rehabilitate nonfederal dams in US. ” quote=”According to the Association of State Dam Safety Officials, it would take an estimated $51.46 billion to rehabilitate the nation’s non-federal dams. “]
Meanwhile, state dam safety offices are historically underfunded with a limited number of staff responsible for inspecting hundreds of dams. This tends to result in a focus on only those larger structures that pose a higher risk to life and public and private property should they fail. Smaller structures may be inspected infrequently, if at all, creating a threat to public safety. While many of these dams are “low hazard,” that is not the same as no hazard. Failure of small dams has been known to wreak environmental damage and cause significant downstream damage to things like driveways or roads.
There are also social behavior issues surrounding dams, which confound safety concerns. People seem to love to play on, in, and around dams. Paddling, fishing, swimming, sunbathing. It all seems fun until you get sucked into the hydraulic undertow.
