Plan prepares for dam failure
Though everyone agrees that the odds of a catastrophic failure at the J. Strom Thurmond Dam are slim, thousands of Columbia County homes lay within the inundation area should such an unlikely event take place. And according to EMA Director Pam Tucker, the revised speed at which the released waters would expand throughout the county make preparedness a necessity.
“In the former plan, the water would take 30 minutes to reach the first tributary,” Tucker said. “In the new information they provided me, it takes six minutes. That’s a big change.”
And because the approximately 800 billion gallons of water held back by the dam would not just go down the Savannah River but would also go up the tributaries, such an event could impact homeowners as far inland as Columbia Road. In fact, the flood area would cover three zip codes.
All of which is why Tucker, who started the plan a year ago, was anxious for the Corps of Engineers to release its data so she could get on with the plan, which was last updated in 2005.
“Once they completed the Thurmond Dam piece, we were able to go ahead with overlaying the population and the inundation area,” Tucker said.
Though she said she is still waiting for data from the corps regarding a cascading dam failure event, which would be the collapse of the Hartwell and Russell dams, Tucker said she was anxious to get the information out to homeowners.
“As soon as I get that information, I will add it in here as well,” she said. “I just wanted to go ahead because I like for people to have an idea of what the plan is and what the arrival times are.”
And while the corps’ revised calculations have drastically increased the arrival of the water, the area’s growth has also increased the number of people living in the inundation area.
“That’s another big change,” Tucker said. “It was 7,000-something before, and now it’s 13,700.”
The plan, which was approved by the Columbia County Commission Tuesday night, is available on the county website and lists each address, road and subdivision in the inundation area. Residents can also use the county’s maps online feature to pull up their specific address by typing in their address, clicking on the layers option, then clicking on environment. A dam inundation option exists, and if a user then refreshes the screen, a colored map shows whether or not the home would be affected by the water.
In late 2011, the Corps of Engineers requested that the county remove the maps from the older plan citing national security concerns, but Tucker refused to sign a nondisclosure agreement and the corps didn’t push it.
In spite of their earlier desire to keep the details of the inundation area secret, the corps’ recent attitude has been to downplay the possibility of a dam failure, something that irritated Tucker.
“The fact that the dam exists mandates that I have a plan,” she said. “Is it the highest disaster on my list of things I’m going to focus on every day? No. We do this plan so people know there is a plan. I’ve learned that people aren’t terrified of these things for the most part, but they want to know that you’re doing the best you can do to warn them, and that you have provisions for them when they do have to leave their homes.”
Tucker has set up a reverse 911 for three groups, starting with those closest to the river. In addition, she would be able to activate the Emergency Alert System, NOAA radios and other systems.
“We actually have encoders in the Emergency Operation Center so that, for anything that’s not weather related, we can activate it from here,” she said. “We also have encoders in the Mobile Operations Center. We don’t have to ask anybody to activate the systems — we can do it ourselves.”
Should such an event occur, the dam failure plan would yield to other plans once the initial warning phase concluded.
“It’s just with the dam we had to have the plan just to itself because it’s a fixed location and you know exactly where the water’s going to go based on the geography,” she said. “You can’t do that for tornados or other emergencies.” You Might Also Like: