Nearly a dozen years after studying the potential benefits of a flood diversion canal, the U.S. Army Corps of Engineers remains concerned about the proposal.
Corps officials have not sought additional funding for an update to their 2009 canal study, but Horry County leaders have again begun discussing the need for such a project.
“Things have changed dramatically here in the last 11 years,” Horry County Council Chairman Johnny Gardner said. “I think [upgraded] technology justifies some further work on that.”
A flood mitigation canal was first proposed in the 1930s. The idea was to take the canal from the Waccamaw River near the state line and continue it about 6 miles to Mullet Creek in the Little River area. The canal would be about 150 feet wide and 18 feet deep.
Essentially, the canal would be a large ditch that would remain dry unless there are heavy rains in North Carolina. The canal would divert floodwater from the Waccamaw River to the coast.
But government agencies and conservation groups have generally panned the project because of concerns about the canal’s cost and environmental impact. Public records show some officials feared the project would cause “severe irreversible harm” to wetlands, and they also worried the canal would give residents in low-lying areas a false sense of security.
Corps spokesman Sean McBride said in an email that the federal agency is willing to coordinate with the county to find out if they are interested in sharing the costs of more research. However, he noted that “the Army Corps remains concerned that the benefit-cost relationship has not improved over time and that environmental impacts remain significant."
As early as 1966, Corps officials worried the expense of building the canal would outweigh its benefit. And in 2009, the Corps projected the canal would cost just over $118 million. The project would also require the construction of five bridges to accommodate roads and a flow-control weir. The estimate, however, did not include the cost of dealing with environmental concerns.
“Any costs required for environmental mitigation are not known at this time and thus not included,” the report said. “The magnitude of these costs would be substantial and would not be incidental; however, without extensive analysis a dollar figure would have no basis.”
In the 2009 study, federal officials noted the project would lower the river level by about 1.24 feet during a 100-year flood, an event with a 1% chance of happening in a given year.
During Tuesday’s council meeting, county leaders spent nearly an hour discussing flooding issues.
Much of the conversation focused on councilman Tyler Servant’s questions about whether Duke Energy’s North Carolina dam system could have better managed floodwater during some February storms. That month, residents in the Socastee community of Rosewood saw their homes flood.
Heavy rains in North Carolina flow into river systems that make their way to Horry County en route to Winyah Bay in Georgetown County. Servant questioned whether the volume of water released into the Great Pee Dee River near the Blewitt Falls Hydro Station in south-central North Carolina played a role in the severity of local flooding downstream.
Duke Energy, which owns the station, sent representatives to Tuesday’s meeting to address those questions.
Jeff Lineberger, Duke’s director of water strategy and hydro licensing, said most of the heavy rains from storms in February fell below Blewett Falls and could not be managed by the North Carolina-based lakes.
Even if the rain had fallen in that area, Lineberger said the hydropower reservoirs are too small to control flooding from such extremely heavy downpours. He compared it to draining a swimming pool into a five-gallon bucket.
“A five-gallon bucket fills up really, really fast,” he said. “It does a little bit for you, but it doesn’t do a whole lot for you.”
Lineberger also pointed out that the hydro turbines at the Blewett Falls station were damaged during Hurricane Florence in 2018 and are not back in service yet. That means they could not release water ahead of time to prepare for the February storm’s deluge. He expects the repairs will be done this year, but even then he said the facility’s flood management abilities are limited.
“It’s not going to be a gamechanger,” he said.
Lineberger stressed that Duke Energy tries to manage the release of floodwater, but that ability is limited.
“It’s not a matter of ‘Let’s release it as fast as we can,’” he said. “It’s ‘Let’s release it as safely as we can.’”
Although Lineberger said Duke is making improvements to its dams, Servant maintained that the energy provider should have invested more money in Blewitt Falls sooner to make the facility better equipped to manage flooding.
“Not to sound trite, but it’s a tough sell to the residents that had their homes flooded out,” Servant said.
When other council members asked about what could be done to mitigate the flooding here, Lineberger told them they have few choices.
“This is not what you want to hear,” he said. “I’m not sure there is a way to control flooding down here in this river system. … There is not a good solution that I see.”
Lineberger did address the diversion canal that was studied in 2009.
He said the Corps focused primarily on the economic challenges with the canal as opposed to environmental ones, but he said the environmental issues could prove more problematic. He said one of the biggest struggles for Horry County is that the rains have been unrelenting in recent years.
Lineberger said 2018 and 2019 have been two of the wettest years he can remember during his three decades at Duke Energy, and 2020 is on track to be the wettest since Duke has had a rain gauge.
“We’re in a period of really, really repeated rain — event after event after event,” he said. “And it doesn’t give that big sponge any time to dry out.”
Councilman Harold Worley asked Lineberger if the Corps study was flawed.
Lineberger, who said he’s read the executive summary of the 2009 report, said he didn’t see flaws in the research, but he noted there are challenges posed by the project.
The U.S. Environmental Protection Agency (EPA), the National Oceanic and Atmospheric Administration (NOAA) and the S.C. Department of Health and Environmental Control (DHEC) all criticized the proposal in letters submitted to the Corps for the last study. Conservationists and scientists also disagreed with the canal idea.
They raised concerns about flooding potential in the North Strand because of diverting water. They also worried about losing wetlands and altering the habitat of shrimp and blue crabs. Critics urged the county and the Corps to look at alternatives to the canal.
“I am unable to identify any potential significant environmental benefits associated with the proposed project,” wrote Dennis Allen with the University of South Carolina’s Baruch Marine Field Lab in Georgetown County. “The long and far-reaching negative consequences identified above and others which are likely to emerge with closer study convince me that this proposed project should not be supported.”
However, if the county wants to revisit the canal project, Duke’s Lineberger said they will have to communicate with the Corps.
“If you’re going to look at physical changes that will impact flood control, you have to talk to the Army Corps,” he said.
Lineberger also noted that the county could look at other options for flood resiliency, including making policy changes that limit where developments can be built.
“The interest is to have people in this river, this set of rivers here, coexist in a less conflicting environment,” he said. “I would encourage you to take a fresh look. … Don’t go in with preconceived notions about what will and what won’t work.”
After the meeting, Gardner said the county will need to work with federal officials on the canal issue. The chairman, who earlier this year appointed a committee to look for possible flooding solutions, said he’s willing to consider other options, too.
“We’ve got millions if not billions worth of dollars worth of damage as a result of this water,” he said. “And I think the Army Corps of Engineers needs to step up, and I think North Carolina and South Carolina should coordinate this together, and I think this is a very big emergency for Horry County and we need to get everybody involved to step up to the plate and do what they can do.”