SC salt marshes are being threatened. What are plans to help preserve them?

Sea-level rise and erosion are threatening South Carolina’s nearly 350,000 acres of salt marsh, among the highest acreage on the East Coast.

To combat the threats, the South Atlantic Salt Marsh Initiative, headed by Pew Charitable Trusts, launched a regional effort spanning from North Carolina to Florida to protect a 1 million-acre tract of salt marsh, comparable to the size of the Grand Canyon National Park.

“We are in a good position where we have healthy, intact salt marsh,” said Lora Clarke, Pew Charitable Trusts senior officer of U.S. conservation. “But we also have a chance now to save it and make sure future generations also have access to this salt marsh, because the decisions we make now will last forever.”

The National Oceanic and Atmospheric Administration estimated nearly 80,000 acres of wetlands in the U.S. are lost each year, including salt marshes. NOAA researchers predict to lose 14% to 34% of salt marshes along the South Atlantic by 2060 if sea levels continue to rise as expected. Salt marshes provide $2.5 billion annually in flood protection to South Carolina’s coastal communities.

A 2023 regional plan recognized the need for North Carolina, South Carolina, Georgia and Florida to each develop its own roadmap for conservation and preservation, which were announced last week. South Carolina’s plan includes increasing accessibility to living shorelines, studying beneficial use of dredged material, removing barriers to marsh migration and educating local government and landowners on preservation priorities.

The Nature Conservancy organized South Carolina’s plan, but more than 100 organizations and individuals came together to provide research, funding and action.

“This was a highly collaborative effort in developing the roadmap,” said Susanna Hopkins, The Nature Conservancy South Carolina resilience program manager.

Approximately 50% of the state’s salt marshes are in Beaufort County. Horry and Georgetown counties have fewer salt marshes, partly due to development, but it also is the area’s natural hydrology.

“While there might be less salt marsh in the north coast, it’s just taking on that much more pressure. Not only from the wave energy and the coastal erosion, but also from the development that we’re seeing all across our state,” Hopkins said.

She said due to the state’s boom in development, land preservation is essential to accommodate salt marsh migration. The roadmaps act as a guide for planning future development, but she recognizes the need for a healthy balance of both preservation and building coastal communities.

“Anybody looking at this roadmap can learn about...the value of salt marsh and its importance, not just ecologically, but culturally and historically,” Hopkins said.

What strategies is the state emphasizing?

Increasing access to living shorelines. South Carolina Department of Natural Resources has led the state in living shoreline projects through its South Carolina Oyster Recycling and Enhancement program. Recycled oysters are either bagged or constructed into manufactured wire reefs and are placed along salt marsh shorelines.

South Carolina is a substrate-limited state, Clarke said, meaning there are a lot of oyster larvae in the water but not enough sediment for them to settle on and grow.

Previous projects have proven to slow salt marsh erosion by providing breakwaters, and they also boost water quality and replenish oyster recruits. But there are gaps along private land as design costs and permitting timelines have created barriers to implementation.

The Nature Conservancy established a pilot program to develop a living shoreline community assistance program that will provide a fully funded design and permitting process in underserved communities.

Implementing a pathway for the beneficial use of dredged material. Over 200 million cubic yards of material are dredged from federally-maintained navigation channels annually. The U.S. Army Corps of Engineers has a goal to reuse at least 70% of the dredged material by the end of 2030.

In the late 2010s, years of erosion and a series of storms severely eroded Crab Bank Seabird Sanctuary, a critical nesting and refuge area for birds located off the Charleston Harbor. A 2021 dredged material project took the eroded island from less than half an acre to 32 acres. It is the only project of its kind to exist in South Carolina.

Now Hopkins said they are looking to use dredged material for marsh platform elevation to keep up with rising sea levels, but proper research has not fully formed regulations for widespread projects.

“There’s a lot of concern, because we don’t want to be dumping mud all over all of our great marshes,” she said. “We’re still developing tools and methodologies to be able to determine the success of one of these projects before we put it in the ground.”

The SC Sea Grant Consortium is developing an economic and regulatory feasibility study to determine the benefits of “thin-layer placement” of dredged material in salt marshes, and it is expected to be completed by the end of 2026.

“It is exciting to see all of these entities with different interests coming together to try and make this practice work, that has seen great success elsewhere,” Hopkins said.

Removing barriers to marsh migration and prioritizing land preservation. Migration of salt marshes is already happening, and it’s especially seen driving along Highway 17 where forests have begun to die off, Hopkins said.

“That’s all salt water coming into these systems that have been historically fresh,” she said.

More than 250,000 acres of South Carolina land are expected to become salt marsh habitat if sea levels rise 1.5 feet. The ACE Basin National Estuarine Research Reserve and SCDNR developed a mapping tool to determine the most vulnerable places for marsh migration.

Marsh migration is a natural and welcomed event, Hopkins said, but it’s often blocked by development. Without proper channels for the marsh to move inland, healthy marsh can degrade.

The goals outlined in the roadmap are to conduct a full inventory of barriers and dams in the state’s coastal areas, prioritize barriers for removal or replacement and collaborate with local communities on resilient design standards, among others.

While South Carolina’s salt marshes are already protected by the state environmental services Bureau of Coastal Management, areas vulnerable to migration are a priority for land preservation.

“We do want to ensure that the land that isn’t salt marsh right now will be able to become salt marsh and isn’t built over or developed in the future,” Hopkins said.

While the South Atlantic Salt Marsh Initiative has identified the strategies, local communities and governments can help plan for and implement many of the goals set forth in the roadmap. While at last week’s state resilience conference, Clarke said it was encouraging to see a united stance on conserving the state’s resources.

“Different political parties, different stakeholders, different groups are all recognizing that South Carolina is one of the fastest growing states in the nation, and that people moved here because they really love the natural resources,” she said. “It’s even more important now to protect those.”

This story was originally published April 30, 2026 at 5:00 AM with the headline "SC salt marshes are being threatened. What are plans to help preserve them?."