Hilton Head Island town officials are calling Hurricane Matthew a “1,000-year flood.”
As such, the ensuing floodwaters from the Category 2 storm that made landfall Oct. 8 overwhelmed many of the drainage mechanisms in place on the island, resulting in damaging flooding in Hilton Head Plantation, as well as along Main Street.
The storm brought 18.28 inches of rain to the area in 24 hours, according to town manager Steve Riley.
“We had pump problems, and we had a rainfall event beyond anything we’ve had in our modern time, as far as the design and capacity of the system,” Riley said.
Flooding in the Headlands
One of the most flooded areas in Hilton Head Plantation was the Headlands area, which is close to stormwater drainage lagoons in the gated community.
A home owned by Jay Dezeeuw and adjacent to a lagoon on Fallen Arrow Drive was flooded by about a foot of water, he said. That water didn’t recede until about 24 to 36 hours after the hurricane had passed, he said.
According to pictures he shared with an Island Packet reporter, the floodwaters in the Headlands appeared to rise nearly to the red of a nearby stop sign.
Dezeeuw rents the home to a family with children and dogs.
The family has had nowhere to live in the wake of the hurricane since the floodwaters ruined nearly everything in the house.
“The big issue they’re having is that there’s no available short-term rentals, and those that are available, in most cases, they’re double the price,” Dezeeuw said. “Even though they’ve been calling daily, they just haven’t been able to find anyplace. … Trying to find a rental that will take pets as well as a lot of little kids is not easy going.”
On Tuesday, nearly all of their possessions — a loveseat, at least four mattresses, carpets, bed frames, dressers and sundry items — were still drying in the sun.
We’re doing everything we possibly can to get them back in this home.
Jay Dezeeuw, homeowner in the Headlands
“We’re doing everything we possibly can to get them back in this home,” Dezeeuw said.
In a worst-case scenario, he said, he will have to replace at least four feet of drywall and the insulation behind it to ward off mold. There’s no word yet on whether the floodwaters affected the house’s electrical wiring.
“There are going to be kids back in this house. We don’t want mold issues,” he said.
Measures to prevent flooding
Dezeeuw recently inherited the home from his parents, who had previously lived there for about two decades.
The Headlands had similar flooding problems after major storms in the mid-1990s, he said.
At least partially a result of that flooding, the Jarvis Creek Park Stormwater Pond and Wetland Project was completed in 2001 to help improve drainage in the area.
The project, which was a collaboration between Hilton Head Plantation and the Town of Hilton Head Island, involved the construction of pumps to move excess water to a lake in nearby Jarvis Creek Park.
In total, the project cost $4.28 million, according to the Savannah Morning News.
Dezeeuw questioned why those improvements had failed to prevent flooding during Hurricane Matthew.
“I thought the engineering work they did ... years ago would have solved this problem,” he said.
It is considered common practice to lower water levels in drainage ponds and lagoons before major storms hit to prevent the water from overflowing and causing flooding.
Hilton Head Plantation did lower its lagoon levels — as town officials think every other community did as well — but doing so likely had little effect, officials said.
“The rain gauge we have in the middle of the island near Shipyard Plantation read about 18.25 inches in 24 hours. That by far exceeds any of the design standards that these ponds and systems are expected to convey,” said Jeff Buckalew, town engineer. “Had it been a smaller storm with much less rain, you (could) lower the lagoons, the rain would fill them up, and it would have a big effect.”
Hilton Head Plantation general manager Peter Kristian said people sometimes have misconceptions about stormwater lagoons.
When you lower lagoons, some residents have some expectation that there’s a plug on the bottom of the lagoon; you pull it out and it goes away. That’s not the case.
Peter Kristian, general manager, Hilton Head Plantation
“When you lower lagoons, some residents have some expectation that there’s a plug on the bottom of the lagoon; you pull it out and it goes away. That’s not the case,” Kristian said. “The lagoon levels are controlled by fixed structures. Sometimes you can lower them inches, sometimes a foot, but that’s about the extent of the elevation you can do.
“If you’re doing it on a high tide, you’re not going to get that much drainage.”
After Hurricane Hermine dumped rains on South Carolina in September, the water table in the area was already high, Kristian said.
“You lower the lagoons, and all you’re doing is seeping it out from ground level,” he said. “You don’t get much more capacity under that combination of circumstances.”
Drains clogged, pumps offline
Clogged drain pipes were a major factor contributing to the flooding, Riley said.
Debris follows the flow of the water, so when hurricanes strike and cause massive damage, tree branches, leaves and other debris stack up against the drains.
“We found large blockages of debris that were blocking the pipes,” Riley said. “There’s grates that keep the big stuff from clogging up the inside of the pipes that go under (U.S.) 278. Those grates were actually bent inward from the pressure from the pipes trying to draw the water through, but just not being able to.”
Flooding during Hurricane Matthew was largely the result of exceptionally high rainfall totals, clogged drain pipes and damaged pumps.
The storm also damaged some of the town’s drainage pumps, including at Jarvis Creek and Sea Pines.
Repair work to homes in the Headlands is well underway.
“We’re going to get through this, and we’re going to make it better,” Kristian said.