Will my property flood? New tech looks to predict who will flood, and when

·6 min read

Aboard the Coastal Explorer — a research boat owned and operated by Coastal Carolina University — researchers launched a torpedo-shaped sonar device into the Intracoastal Waterway Monday. That device, tied to the Coastal Explorer, cruised near the bottom of the channel, mapping out the riverbed and collecting volumes of data that researchers can use to determine how fast water can move through the channel, and what might get in its way.

Another boat, working alongside the Coastal Explorer, ferried another research device along its port side, this one able to calculate and monitor how fast fresh water moves South towards the Winyah Bay and how fast salt water moves North.

Across from the Osprey Marina in Socastee, a team of three state National Guardsmen dove into the Waterway to attach water-quality monitoring devices to a buoy floating near the water’s edge. And atop a post at the end of the dock, researchers installed several weather and atmosphere-monitoring devices that will fill out the data puzzle now deployed in Horry County waters.

Taken together, those new devices and research efforts by Coastal Carolina researchers could piece together data that’s not been available previously that could help determine which parts of Horry and Georgetown counties are most likely to flood and when. The hope, shared researchers and lawmakers alike, is that the data be used to better predict which specific properties could experience severe flooding. That could allow residents to know if their home is at risk of flooding during a particular storm and could allow local lawmakers to make better-informed decisions about zoning and building.

If the data is able to do that, it could prove to be a better risk-assessment tool than those currently available, including the maps the federal government produces to predict which properties are likely to flood.

By combining information about the atmosphere, water quality, water speed, the riverbed and more, researchers said Monday that they could model and predict which tracts of land are flood-prone, when unexpected areas might flood, and more. Because the Grand Strand is so flat, flooding is not caused just by over-filled rivers moving stormwater from North to South — it’s caused by ocean waters moving into the rivers and preventing that drainage, too. Those areas where fresh and salt water collide have been difficult to measure in the past, researchers said, and the new monitoring tools could help solve that problem.

“When you have intense rainfall, you have pressure coming from the Waccamaw River and then after the rain moves by, you have wind blowing on shore so you have water from the ocean coming up the Winyah Bay,” explained Trevor Carver, one of the CCU researchers collecting data. “It’s Socastee, it’s Conway, that’s where they meeting.”

CCU researchers hadn’t previously been able to access specific data on those phenomena, Carver and other researchers said.

“If we can know how fast the water is coming down the Waccamaw River, how fast that tide is coming up Winyah Bay, we can probably get a better idea of where they’re going to meet and where the giant pressure is going to be,” Carver said.

State officials and local policymakers said Monday that they hope the new data about how water moves through the Grand Strand can better inform state laws, flood mitigation programs, local development and more.

Horry County is currently working to launch a home buyout program for several dozen homeowners in the Socastee area who have flooded multiple times in recent years. While programs like that can help move people out of harms way, they’re not a perfect solution to the area’s flooding problems, said state Rep. Heather Ammons-Crawford, who represents the area.

“We can’t relocate the entire Pee Dee and all of Socastee, so this research is so important for us,” she said at a press conference aboard the Coastal Explorer before the new devices were launched. “We know that one of the issues we’ve had in the Socastee area is the lack of a warning system, an effective warning system, to notify residents when the water will rise. This today...will help with that notification.”

By combining weather data with flood-monitoring data, the CCU researchers said that information could help residents at risk of flooding know when to leave home, developers know where to build and policymakers know how to craft better regulations.

“We’re projecting into the future,” said Paul Gayes, the director of CCU’s Burroughs & Chapin Center for Marine and Wetland Studies, and the lead researcher on the project. “This is how the flooding is going to change, this is what the landscape is projected to change into, what’s going to flood and what are those costs. When we start linking all of that together, the actual science, the economics, what’s at risk, and what risk really is, I think we can have better management.”

The new research program is called the Smart River Research Program, and is one of the implementations of the South Carolina Floodwater Commission’s major 2019 report. That report said, in part, that one of the ways South Carolina can reduce its risk from flooding is to better monitor water and weather along its rivers, inlets and bays. Retired Maj. Gen. Tom Mullikin, who leads the Floodwater Commission, said the monitoring devices deployed Monday were a manifestation of the research and “academic” work that’s been done in the past, and one that can now apply that work to better residents’ lives.

“We’re not talking about academic issues anymore, we’re talking about issues that impact people’s lives,” Mullikin said. “We’re no longer modeling, we’re measuring. When you have people being flooded out of their house 15 times in three years, we have a dire issue.”

The Duke Energy Foundation, which partnered with CCU on the initiative, is pumping $100,000 into the effort to help fund some of the monitors, which will fill in data gaps that the federal government doesn’t collect. State Sen. Stephen Goldfinch said he hopes the foundation’s investment is an initial one and could lead to larger projects in the near future.

The new data initiative also comes at an opportune time for Horry County. A special commission of local lawmakers, county officials and environmental advocates has been meeting since December last year to study flooding in Horry County and recommend policy changes the county can adopt to mitigate the effects of flooding. The commission is currently work-shopping new building regulations that could affect how high above flood levels builders will have to construct new housing and businesses.

Gayes said his team hasn’t worked directly with the county flooding commission but said the data they’re collecting could aid future policy discussions. Dan Ennis, CCU’s provost, said he hopes that’s one of the outcomes of the project.

“The work done through these experiments, through this data collection, through this analysis gives everyone an objective understanding of the challenges our community faces,” he said. “And, (it) therefore provides information to the community to make intelligent policy choices.”

Editor’s note: This story has been updated.

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