Intertidal Marsh Hydrology and Geomorphology

University South Carolina Research Foundation, Columbia SC

Investigators

Abstract

0229358 Voulgaris Sea level rise and coastal urbanization have unknown effects on tidal creek habitats because feedback between tidal forcing and marsh morphology are not well constrained. In the south Atlantic Bight, tidal creek networks etch marsh surfaces and produce subtle but well-defined drainage basins. We propose to conduct exploratory research designed to elucidate the interactions between process and form in a pristine marsh, representative of marshes in the south Atlantic Bight. The objectives of this proposal are to analyze the linear, aerial and 3-D structure of a marsh basin, and investigate how interactions between tidal flow and topography influence basin evolution and stability. Our research goal is based on the modification and application of terrestrial geomorphology models that rely on the watershed basin area (process) to explain river networks (form). In a similar manner we seek to identify if a creek basin area can be used to characterize creek form and further to define such creek basin area. This can be accomplished using high-resolution DTM (digital terrain model) of a marsh area and evaluating the morphology of its tidal creek basins Delineation of basins identified in the DTM (using topographic highs) will be compared to basins defined by flow divides, which in a tidal environment might not coincide with the marsh topographic highs. Flow divides will be defined for various tidal stages and ranges using a 2-D depth averaged, finite element hydrodynamic model. Both types of basins will be compared and analyzed for creek length, basin area, slope and drainage density, hypsometry and inundation frequency, and these parameters will be tested for scale invariance. This initial pilot study will be carried at a location in North Inlet, SC a pristine marsh system. The results of this work will help set guidelines for intertidal zone habitat restoration and rehabilitation.