U.S. coastal marsh restoration: The role of sediment placement Shore & Beach

Coastal marshes are important ecosystems that provide numerous services but are rapidly becoming more vulnerable to degradation and erosion due to the effects of climate change. These effects jeopardize erosion control and storm protection, wildlife habitat, water quality, carbon sequestration, recreation, and other coastal-marsh benefits. As a result, determining marsh health and optimizing delivery of these services represents an important endeavor for coastal scientists, engineers, and managers. One option for improving marsh resilience and ecosystem function is sediment placement for expanding or restoring marshlands. However, coastal marshes in the United States vary in size, shape, and vegetation depending on the climate, boundary conditions such as geology, sediments, influx of freshwater, and external forces including wind, waves, currents, and tidal range. Coastal marshes in the Northeast, Mid-Atlantic, Southeast, Gulf Coast, California, Pacific Northwest, and noncontiguous U.S. are described, including their extent, value, and restoration needs. Examples of sediment placement marsh restoration projects in these regions are provided. Outlined is the current state of knowledge about sediment placement in coastal marshes, as well as current approaches to sediment placement across the United States. There is also a discussion of current best management practices (BMPs), including limitations of these projects.