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Flows, transport, and form drag in intertidal salt marsh creeks
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  • Collin J Ortals,
  • Orlando Cordero,
  • Arnoldo Valle-Levinson,
  • Christine Angelini
Collin J Ortals
University of Florida

Corresponding Author:[email protected]

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Orlando Cordero
University of Florida
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Arnoldo Valle-Levinson
University of Florida
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Christine Angelini
University of Florida
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Abstract

Intertidal creeks (<5m width) weave through salt marshes, delivering water, nutrients, and sediments into the marsh interior and alter spatial heterogeneity in plant and animal distributions. Despite their global prevalence, creek connectivity, and the mechanisms controlling cross-marsh hydrodynamics, remain poorly resolved. In this study, we measured flow and total suspended solids (TSS) transport in three intertidal creeks within a confined drainage basin in a Georgia, USA salt marsh. We discovered that the effective drag is 3 to 12 times greater than bed drag, reaching levels similar to those observed in coral reefs. Furthermore, the drag between tidal flood and ebb phases differ, suggesting a non-symmetric drag. Analyses of along-channel momentum reveal that the friction O(10E-3 - 10E-2 ) and pressure gradient O(10E-3 - 10E-2) dominate creek momentum balance. Divergence in tidal and TSS transport between adjacent creeks reveals opposing tidal asymmetries within this confined basin. We suggest that these differences may mediate the eco-geospatial evolution of salt marshes and their response to sea level rise.