The Importance of Sediment to Northeast Salt Marshes and Threats Posed by Regional Decline in Coastal Sediment Supply

Coastal environments such as salt marshes, shellfish flats, and beaches depend on a continuous supply of sediment to adjust to rising sea levels. For several years, an NE CASC-supported team has been focusing on assessing (1) the dominant sources of sediment to the New England coast, (2) how sediment contributes to salt marsh health, and (3) how humans may be reducing coastal sediment supplies in the Northeast US. In this webinar, team members will first illustrate the relationship between sediment supply and the ability of salt marshes to build vertically, a process that is essential to maintaining a platform elevation above rising sea levels. Second, the team will compare the sediment delivery to the coast from rivers to that derived from coastal bluff slumping using lidar differencing to quantify the amount of sediment being added directly from bluff erosion. Finally, team members will conclude by making use of a newly developed satellite remote sensing tool to demonstrate that coastal suspended sediment has been declining in the Northeast US. They hypothesize that extensive coastal armoring is partly to blame for observed decreases in coastal suspended sediment, potentially posing added adaptation challenges to threatened coastal habitats like salt marshes. 

Brian Yellen is the Massachusetts State Geologist and a faculty member at UMass Amherst.  Dylan Roy is a graduate student in the Department of Earth, Geographic, and Climate Sciences at UMass Amherst. Wenxiu Teng is a graduate student in the Department of Earth, Geographic, and Climate Sciences at UMass Amherst.  Jon Woodruff is the NE CASC University Codirector and a faculty member in the Department of Earth, Geographic, and Climate Sciences at UMass Amherst.