Beach Nourishment in South Carolina

In South Carolina, there are 190 miles of beaches that visitors and residents enjoy year-round. Beaches are also important to the environment and economy. To preserve South Carolina’s beaches, an addition of sand through beach nourishment is sometimes needed along parts of the coast to ensure the sandy shoreline is wide enough for everyone—visitors, residents, and wildlife.

A cross section of a typical beach profile which labels the various parts of the beach. Photo Credit: Dune Book, North Carolina Sea Grant, 2003

What is Beach Nourishment and Why is it Important?

Nourishment replaces sand lost to natural erosion. This is when sand is washed off of the beach into the water. Nourishment maintains a wide beach and robust dunes to ensure the health of the shoreline. Sometimes this process is also called beach renourishment.

A wider beach provides a natural environment for endangered sea turtles and birds, and provides storm protection for oceanfront homes, infrastructure, and businesses. It also allows beachgoers to spread out, recreate, and enjoy the environment.

How Often is Beach Nourishment Needed?

The need for beach nourishment depends on weather conditions, storms, and natural erosion processes. It is typically needed every four to eight years.

How do Beaches Erode?

Most beach erosion is naturally occurring. Under normal conditions, winds shape the dry part of the beach and its dunes while tides, currents, and waves shape the wet part of the beach. The daily ebb and flow of water continually shapes the shoreline. It is natural for hurricanes and coastal storms—which move huge volumes of sediment through the system—to erode beaches.

A cross section of a beach profile after it has experienced erosion from a storm event. Photo Credit: Dune Book, NC Sea Grant 2003

How Does the Beach Change with the Seasons?

If you visit the same beach location throughout the year you may notice that in the winter the beach is often flatter. This is because the sand that makes up the berm (the sloped part of the beach) has been moved offshore by waves, currents, and tides.

In the summer this offshore sand will be pushed back onshore through wave action and the berm will build back up. This movement of sand is called cross-shore transport.

Cross-shore transport helps beaches naturally recover from storms. However, sometimes the storms move too much sand or occur too close together so that the natural recovery process needs an additional influx of sand. This is when beach nourishment is needed.

A cross section of a beach profile showing the difference in the beach in the summer and winter Photo Credit: Dune Book, NC Sea Grant 2003

What Other Coastal Processes Affect Beaches?

There is a process called longshore transport or longshore drift where sediment is moved by waves and currents along the shoreline. This is also sometimes referred to as littoral drift. Each beach in South Carolina has a dominant direction that the longshore transport moves sand. If an inlet is present, the sand will often move towards the inlet.

Inlets are very dynamic and complex areas where lots of coastal processes are at work to create unique sand movements. Scientists and engineers will often use models to understand how sediment is moving in these areas.

Graphic showing how the longshore current will move sand grains downstream in a process called longshore drift Photo credit: Pearson Prentice Hall, 2004

How is Beach Erosion Monitored?

Beach nourishment is an ongoing process—once one project ends monitoring takes place to determine when the next project will be needed.

There are beach monitoring stations located across the entire coast. The South Carolina Department of Environmental Services Bureau of Coastal Management hires a contractor to collect profile surveys on a yearly basis as these monitoring stations to observe how sand is moving. This profile survey data can be viewed through the Beach Erosion Research and Monitoring Profile Viewer (BERM Explorer).

Aerial photos are also taken by various organizations to monitor how the coastline changes. The S.C. Sea Grant Consortium has also partnered with the US Army Corps of Engineers, Engineering and Research Development Center (ERDC) to provide local communities to help monitor very localized shoreline changes at Folly Beach and North Myrtle Beach through a program called CoastSnap.

What Are the Steps in the Beach Nourishment Process?

Many months (sometimes years) before a project begins, coastal engineers conduct a sand search to locate sand that approximates the same grain size and color as the existing beach.
A beach profile template is designed by engineers. This model shows where beach nourishment is needed.
The engineer applies for permits from state and federal entities, the S.C. Department of Environmental Services Bureau of Coastal Management, and the US Army Corps of Engineers. The project plans are reviewed, and permit conditions for the project are put in place to dictate the environmental protections and other regulations that must be followed.
The engineer asks for bids from contractors to do the work and a contractor (often the one who said they could do the work for the lowest price) is awarded the project.
The contractor excavates the sand by hydraulic dredge from the identified offshore sites and move it through miles of submerged and floating pipeline, from the ocean floor to the beach.

In Oak Island, N.C. a pipe is delivering a mixture of sand and water from the ocean floor to the beach. Behind the pipe, a dredge in the ocean pumps the sand from the ocean floor into the pipe. In the foreground a bulldozer stands by, ready to move the sand into place. Photo credit: Katie Finegan, 2021

The pipes deliver a mixture of sand and seawater to the beach, the water runs back out into the ocean, and bulldozers and other construction machinery construct the elevation and form of the beach with dredged sand. Bulldozers will form a berm (a small sand wall) in the active working area to trap the sand and allow water to flow back to ocean.

Photo caption: In Folly Beach, S.C. a bulldozer forms the berm to trap sand that is being pumped onto the beach by a dredge from an offshore location. Photo credit: CoastSnap, 2024

Watch the Nourishment Process at Folly Beach, South Carolina

How Does Nourishment Affect Beach Visitors?

Although certain inconveniences are unavoidable, beach nourishment is completed as quickly and efficiently as possible. Construction will often take place 24 hours a day, and the active work area will span about 1,000 feet (approximately 3 football fields) along the shoreline.

Visitors near the active work area may hear large construction equipment working and beeping from that equipment backing up. This active work area is closed for a period of time, usually no more than 1-2 days. As soon as the section has been nourished, the construction equipment will progress down the beach and the newly nourished section is immediately accessible.

Caption: In Oak Island, N.C. pipe is laid along the beach to transport sand from offshore to onshore, pipe sections are continuously added to reach new areas to nourish. Photo credit: Katie Finegan, 2021

What Equipment is Used During the Nourishment Process?

The beach nourishment process often involves the use of dredges, a booster pump, and many miles of pipeline through which the sand will be pumped, along with attendant tugboats and barges. The land-based equipment includes numerous bulldozers to shape the new sand, survey equipment to quantify the amount of material that is placed, and support vehicles such as trucks and ATVs.

Some nourishment projects collect survey data of the placed sand through the use of a Coastal Research Amphibious Buggy (CRAB). This unique three-wheeled vehicle looks like something out of a sci-fi movie. The tripod tower is about 35 feet tall and allows the survey to take place both on the beach and out into the water.

In Oak Island, N.C. a Coastal Research Amphibious Buggy (CRAB) collects survey data of the beach prior to nourishing to track how much sand will be added. Photo credit: Katie Finegan, 2021

What Happens After a Beach Nourishment Project is Complete?

First, the newly placed sand often appears quite dark. During the dredging process mud will also be picked up and mixed in with the sand. Within a few days, however, the sun oxidizes the non-sandy material and the beach eventually turns as light as it was before the project.

The beach profile that is created often has a boxy and unnatural shape, as it was constructed using bulldozers and other equipment. Within days of the material being placed, waves will move the new sand around to mimic a more natural beach slope. This process is called equilibration.

Visitors to the beach during this equilibration time may experience a shelf or a step on the beach between the new sand and the existing sand. Within a few weeks the beach slope should be normal again.

A beach profile which demonstrates how nourished sand will equilibrate to a natural beach slope after sand placement occurs. Photo credit: USACE Coastal Engineering Manual, 2002

In Folly Beach, S.C. the beach is experiencing equilibration—the newly placed sand is being shaped into a natural slope by the waves. Photo credit: CoastSnap, 2024