Skip to main content

Keeping it in the System: Beneficial Use of Dredged Sediment to Increase Resiliency of Coastal Marshes in the Southeast (KITS)

The KITS project is a collaborative effort among researchers from The University of North Carolina at Chapel Hill, the National Centers for Coastal Ocean Science, The United States Army Corps of Engineers, and EA Engineering, Science and Technology. The funding for this work comes from the NCCOS Effects of Sea Level Rise Program.

Image Credit: Sam Whitin

Why?

Intertidal marshes grow vertically by trapping sediments carried in tidal waters and an adequate sediment supply is critical for marshes to increase elevation at a rate commensurate with local relative sea level rise (SLR). Marshes will need more sediment to keep up with accelerated SLR. Dredging of navigation channels exacerbates the problem because in most cases, dredged sediments are removed from the estuarine system and disposed in either upland or offshore open-water sites. There is increasing recognition of the value of keeping dredged sediments in their local system and using them to create or enhance Natural and Nature Based Features (NNBF), such as thin-layer placement to salt marshes. Also termed beneficial use, this strategy of repurposing dredged sediments within the estuarine ecosystem can be an effective way to build marsh resilience to storms, SLR, and erosion, thereby protecting the services they provide.

Coastal marshes provide numerous societal services including habitat provision, improvement of water quality, protection of built infrastructure from storms, and carbon accumulation and storage. Models will be used to predict the long-term resilience of salt marshes to SLR, in addition to the rate of carbon accumulation. Loss of salt marsh sediment by erosion and drowning may release a significant portion of the stored carbon in the coastal ocean and contribute to an increase in atmospheric CO2.

 

Image Credit: Restoring America’s Estuaries

What are we doing?

The KITS team is developing a comprehensive approach for maximizing the beneficial reuse of dredged sediments within their watershed of origin, at two different study sites in Beaufort, NC and Jacksonville, FL. The focus of this approach is thin-layer application of dredged sediment to at-risk marshes, which helps to raise the marsh elevation above where sea level rise would otherwise drown the marsh completely. The project will engage local and regional stakeholders as well as the regulatory community, and the lessons learned from our project will be captured and shared with the wider community of scientists and land managers.

 

For more information, check out the project description here

 

Image Credit: Sam Whitin