Vegetation‐Driven Seasonal Sediment Dynamics in a Freshwater Marsh of the Mississippi River Delta

Abstract

Deltaic wetlands are critically important coastal environments, upon which hundreds of millions of people depend. Managing and preserving them in the face of sea level rise will be a challenging task over the next century that will require land managers to devise restoration strategies that maximize the delivery and storage of mineral sediments, and to apportion limited sediment resources to priority locations. We collected a unique field data set characterizing sediment delivery to, and retention in, a deltaic wetland throughout a period of rapidly changing emergent and submerged vegetation conditions in the spring of 2019. Our results demonstrate that wetland deposition is extremely sensitive to the timing of the flood pulse with respect to vegetation conditions, and that vegetation alone can adjust sediment delivery and retention by one or more orders of magnitude over a period of weeks. In planning for wetland management operations, it will be critical for managers to assess these rapidly changing conditions as they influence project success.