Managing Seabrook Island's Dynamic Shoreline

Since 1980, around 22 percent of shoreline on Seabrook Island has gained over 1000 ft of beach or dune width. Soft engineering solutions have buried all but 2500 linear feet of seawall and added upward of 100 acres of beach/dune/beach trust habitat. Seabrook Island POA has sponsored annual monitoring surveys of the beach and uses this information to plan future beach management projects.

To combat beach erosion, seawall construction was used to protect Seabrook's coast throughout the 1970s and early 1980s. Primary measures implemented include sandbags, quarry stone groins, sandbag revetments, concrete sheet-pile bulkheads and quarry stone revetments. The last seawall structure was built in the early 1980s around Renken Point (~1800 ft) and near the Pelican Watch Villas (~900 ft). Since then, SIPOA has switched to soft-engineering solutions, and seawalls are maintained by individual property owners.

In September of 1979, Hurricane David hit the Island and caused severe damage to the seawall around the Beach Club and Renken Point. Major repairs were made to the seawalls at these locations. In the 1980s, seawall collapse occured due to beach erosion, and was later repaired.

Since the 1970's, Seabrook Island has installed around 8800 linear feet of seawall. Since 1983, soft engineering solutions have buried all but 2500 linear feet of seawall. Seawall maintenance and repair projects were completed in 2007 and 2024.

Sand scraping is the movement of sand from the intertidal zone to the beach dunes. Beach scraping is done by mechanical means, usually by heavy equipment. This technique can increase the volume of sand on the beach, decreasing short-term erosion. This is a short-term mitigation technique and needs to be repeated and well maintained. Beach scraping is a good short-term solution with a comparitively low cost and low ecological impact.

Seabrook Island has had 10 sand scraping projects in the past. Each project varied in volume of sand moved, sand source and placement area. Cost of beach scraping projects varied based on location and quanitity moved, but typically ranged from $80,000 to $300,000.

Dredging is the removal of sediment from the bottom of water bodies. Over time, sediment naturally settles, decreasing the depth of water bodies. Often, sediment in the ocean is removed and added to the beach.

In 1990, the northern inlet was realligned by ocean dredging. The ocean-going dredge built a parallel channel 600 feet seaward while filling an exsisting channel along the seawall. This project added 650000 cubic yards of sand to the beach between Pelican Watch Villas and Renken Point. The total cost of the dredging project was $1.6 million.

The 1990 project was the first nourishment project in South Carolina to use an ocean-certified hydraulic dredge. Since 1990, over twice the amount of sand moved has natually collected in the project area, offsetting the natural encroachment rates. Dredging this area allowed the formation of a wider dry beach and a protective dune along a major portion of the beach. No more dredging operations have been required since 1990.

Capn Sams Inlet currently migrates 150 to 300 feet per a year. Sand gets entrapped in the inlet causing beach erosion. Relocating the inlet would allow sand to settle along Seabrook Island's beaches. Capn Sams Inlet has been relocated three times; 1983, 1996, and 2015. The relocation project has a 12-15 year design life.

In February of 1983, Capn Sams Inlet was relocated ~1.5 miles to it's original 1963 location. The new inlet was excavated as an enclosed basin, and formed by breaching an outer derm. The abandoned inlet was enclosed during low tide by bulldozers filling it with surplus sand on either side. The project costed approximately $475,000, significantly more cost effective per cubic yard of sand than other beach renourishment methods.

"The project was both environmentally sensitive and cost effective, indicating the benefits of combining fundamental research on coastal processes with coastal engineering practices" - National Academy of Sciences (1994)

Capn Sams Inlet was relocated ~4000 ft in 1996. This relocation restored >80% of Seabrook Island's shoreline, a gain of nearly 2 million cubic yards of sand. It buried the seawall, expanded the beach, dunes, and salt marsh without using any physical structures. This project was not a permenant solution and further inlet relocation projects were planned for the future. The project's total construction costs was $536,000.

Capn Sams inlet was relocated ~3000 ft northeast from its original location. Excavation was similar to the previous two projects. The 2015 inlet relocation was completed in record time and with minimal disruption to the project area. Around 140000 cubic yards were excavated and 165000 cubic yards were used to create the closure dike. Total construction cost was $930,500.

On May 23rd, 2016, the American Shore and Beach Restoration Association announced the Seabrook Island was a winner of it's 2016 "Best Restored Beach" Award for 2016.

“ASBPA created the Best Restored Beach award as a way of highlighting the value of America’s restored beaches,” said Tony Pratt, ASBPA president and administrator of the Shoreline and Waterway Management Section within the Delaware Department of Natural Resources and Environmental Control.  “As Americans flock to our coastline during the upcoming beach season, most don’t even realize they may be enjoying a restored beach.”

To enter the Best Restored Beach competition, coastal communities nominated their projects for consideration, and an independent panel of coastal managers and scientists selected the winners. Judging was based on three criteria: the economic and ecological benefits the beach brings to its community; the short- and long-term success of the restoration project; and the challenges each community overcame during the course of the project.

A complete list of award-winning beaches, and more information about beach restoration and ASBPA, is available online at  www.asbpa.org .

This storymap was prepared using data and reports from Research Planning Institute, Inc. (1978-1983) and Coastal Science & Engineering, Inc. (1983-Present). The projects were also completed in close cordination with the SIPOA Environmental Commitee. Photos were provided by the Seabrook Island Property Owners Association and Coastal Science & Engineering Inc. Video was provided by Steven Traynum at Coastal Science & Engineering, Inc.

CSE. 2015. Capn Sams Inlet Relocation, Seabrook Island, South Carolina. Final Report to Seabrook Island POA; CSE, Columbia, SC, 61 pp + appendices.

CSE. 2016. Capn Sams Inlet Relocation, Seabrook Island, South Carolina. Monitoring Report to Seabrook Island POA; CSE, Columbia, SC, 77 pp + appendices.

NRC. 1994. Restoring and Protecting Marine Habitat, Inlet Engineering Seabrook Island at South Carolina. 143-144 pg.

Town of Seabrook Island. 2019. Comprehensive Beach Management Plan; Seabrook Island, SC, 1-164 pg.

YouTube. (2019). Capn Sams Inlet Relocation Project. YouTube. Retrieved July 14, 2022, from  https://www.youtube.com/watch?v=19xt39yjqPw.