CAREER: Topographic Controls on Overmarsh Circulation and Sedimentation along a Salt Marsh - Forest Continuum

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Salt marshes remain the focus of intensive study due to their ecosystem functions (i.e. water storage, nutrient redistribution, and carbon sequestration) and in light of potential impacts of sea-level rise and coastal development on their overall stability. The ability of marshes to migrate inland as waters rise is considered a first-order determinant of their future survival. This project is specifically designed to determine the influence of subtle marsh topography on how, when, and where marshes retreat inland. This project will have broad educational impacts by engaging a large number of undergraduate students in field work, design and implementation of a new field teaching laboratory, and a new field-based undergraduate course. Educational aspects of this work are designed to prepare the next generation of geoscientists to address scientific and societal issues related to coastal zone stability. Informal learning for the general public includes the creation of an interactive digital kiosk for the University of South Carolina Aiken Ruth Patrick Science and Education Center designed to increase public awareness of environmental and socio-economic issues associated with coastal zone response to climate and land use change.The primary scientific objective of this project is to quantify the topographic controls on overmarsh flow, sedimentation, and water residence times across a salt marsh – forest continuum within the ACE Basin, SC. The marsh-forest continuum encompasses a natural salt marsh, a reclaimed rice field marsh or “ag-marsh”, and an ag-marsh-forest ecotone, allowing for a space-for-time substitution to advance knowledge on the geomorphic controls on marsh morphodynamics across various marsh types and stages of development. It is hypothesized that the artificial drainages of ag-marshes facilitate hydraulic connectivity of surface flows within and between marsh systems, and with neighboring uplands, thereby enhancing inundation extent and residence times, and influencing rates and patterns of forest-marsh transgression. Hence, this project will help illuminate the role of ag-marsh landscapes as corridors for inland marsh migration in response to sea-level rise. Field observations of in-channel and overmarsh flows, and modern and historic sedimentation rates will be evaluated in the context of marsh topography, drainage structure, hydraulic connectivity and vegetation effects. A computer model will be developed to predict salt marsh response to natural and anthropogenic forcing across local and regional spatial scales, and at hourly to multi-decadal time scales. Such information can be used to bolster coastal vulnerability models, and can help inform policy and decision making strategies related to marsh restoration and conservation. This project is jointly funded by the Geomorphology and Land-use Dynamics Program and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.