Corps Partnership

Every few months and following major storms, a drone can be seen methodically surveying Tybee Island’s coastline. The flights are part of an ongoing project led by researchers in Dr. Clark Alexander’s lab at the University of Georgia’s Skidaway Institute of Oceanography (SkIO).

On a six- to seven-year cycle, the U.S. Army Corps of Engineers pumps sand onto Tybee Island’s beaches to counteract erosion caused by waves, tides, wind, and human activity. The Corps has regularly renourished them since 1975, with a focus on building flat, wide beaches.

Research professional Claudia Venherm pilots a small drone, equipped with LiDAR (light detection and ranging) technology, along the coastline to survey where sand is eroding and where it’s accumulating.

Research technician Kyle Krezdorn prepares a drone for flight to map Tybee Island Beach.

Venherm then creates detailed maps of her data to share with the city of Tybee and to guide the Corps’ future nourishment efforts.

“Because of SkIO’s data, we know for a fact where it (sand) is eroding, where it is accreting, and how fast it has been eroding,” says Alan Robertson, who manages beach nourishment projects for Tybee. “I take a lot of pride in the fact that the Corps is using our data, provided by Skidaway, in the design.”

Making History

The Army Corps of Engineers’ decades-long work on Tybee Island nourishment stems from the Corps’ maintenance of the shipping channel leading into the Port of Savannah. That maintenance disrupts the natural flow of sediment from the north that would otherwise naturally replenish Tybee’s beaches.

For the first 45 years of the partnership, the Corps focused solely on adding sand to the beach, keeping conditions ideal for the nearly two million beachgoers who visit the island each year. But during the last nourishment project in 2020, the Corps added extra sand at Tybee’s request that the city used to create a complex row of dunes as well. Dunes serve as natural barriers, guarding Tybee’s community and infrastructure from potential storms and hurricanes.

“People hadn’t created dunes for the purpose of protecting against storm damage in the state of Georgia before,” says Alexander. “These were functional dunes to provide sacrificial sources of sand if we had high sea levels and intense storms. This was the city being very proactive.”

Initially, Tybee brought the Alexander Lab on to monitor the new dunes. Once it became apparent that the dunes were stable, the project grew to include the complete beach profile.

Data in Action

As Venherm flies the drone, she’s joined by others from the Alexander Lab. Research professional Mike Robinson walks along the beach with a real-time kinematic GPS to help the drone provide more precise geospatial data. Kyle Krezdorn, also a research professional, monitors the drone’s flight.

“What we are trying to do is see the changes,” Venherm says. “I measure the elevation of the beach and the dunes and look at how that changes every three months. And then I can say if there is erosion or accretion of sand.”

That data informs the Corps about where and how much sand to pump onto the beach; it also builds confidence and trust in the public, whose tax dollars help fund the nourishment projects, Robertson explained.

Beach renourishment not only safeguards communities and critical infrastructure, but also ensures Tybee Island, known as “Savannah’s beach,” remains a popular destination during peak tourist season. Tourism revenue is vital to the coastal economy, and this project exemplifies how beach nourishment delivers economic, environmental and resilience benefits.

“Now that we have five years of data, we can start to project,” Robertson says. “We can tell the public, ‘Here’s where you can expect there to be no beach next summer season at high tide.’ We can get ahead of that. We don’t have to be reactive.”

With these insights, Tybee and the Corps are preparing for the next beach nourishment project, scheduled to begin in November 2026, and safeguard the island community and its guests.

Research professionals Mike Robinson (left) and Claudia Venherm prepare their LiDAR-equipped drone on the Tybee Island Beach.