Enhancing Marsh Resilience by Adding Sediment

About this project

Through this project, replicated restoration experiments are being conducted at several reserve sites across the nation, with the purpose of examining the effectiveness of thin-layer sediment placement as a marsh adaptation strategy. Novel aspects of the project include the broad distribution of sites, the examination of the effectiveness of thin-layer sediment placement at different marsh elevations, a standardized monitoring protocol, and the incorporation of biochar (carbon material produced through the conversion of biomass in an oxygen limited environment) to improve soils and plant health.

How this project will help

Tidal marshes provide key ecosystem services—and they are increasingly threatened by sea level rise. Narragansett Bay and Elkhorn Slough National Estuarine Research Reserves recently led the first national assessment of tidal marsh resilience to sea level rise by developing and applying multi-metric indices to 16 reserve sites. Now the group is moving beyond marsh resilience monitoring and assessment efforts to actively test strategies to enhance resilience.

Beneficial use of dredged sediment to enhance coastal resilience is of interest to, and already being applied in, many coastal states. At project conception, the team interviewed and surveyed end-users involved in funding, permitting, implementation, and monitoring of thin-layer sediment projects. This project will address the needs end-users identified, including a vetted monitoring protocol to assess restoration success after thin-layer sediment placement, a synopsis of associated permitting issues, and an evaluation of effectiveness of different treatments detailed in a technical report and summarized in a brochure and webinar.

The overarching goal of the project is to enhance salt marsh resilience by filling critical data gaps and providing information that will allow future thin-layer sediment placement projects to move forward more efficiently, in places where they will be most effective. Anticipated benefits include the following:

  • Development of a national framework for enhancing coastal resilience through thin-layer sediment placement;
  • Improved site selection and enhanced effectiveness of future sediment addition projects;
  • Standardized monitoring across future projects;
  • Establishment of appropriate performance measures


Chris Peter, Research Coordinator
Great Bay National Estuarine Research Reserve