Title

Sediment Transport Processes in a West-central Florida Open Marine Marsh Tidal Creek; the Role of Tides and Extra-tropical Storms

Document Type

Article

Publication Date

8-1995

Digital Object Identifier (DOI)

https://doi.org/10.1006/ecss.1995.0063

Abstract

The extensive open marine marshes on Florida's Gulf of Mexico coast constitute one of the largest continuous coastal marsh systems in the U.S.A. and are characterized by (1) the absence of an apparent modern or relict sediment supply, (2) a thin 1-2 m sediment veneer overlying highly karstified bedrock and (3) both low wave and low tidal energy regimes. More importantly, the Florida open marine marsh system appears to be keeping pace with current rates of sea-level rise in spite of a limited inorganic sediment supply and low tidal energies. Although the magnitudes and directions of suspended solid transport and the processes controlling these transports have been rigorously documented for other U.S.A. marsh systems, they have not been documented in the Florida marsh system. Total suspended solid (TSS) concentrations, current speeds and water levels were monitored in Cedar Creek, Florida, so that the TSS loads could be calculated and the processes exerting control over material exchange could be determined. Both TSS concentration and load are modulated by spring/neap variations and time-velocity asymmetries in the tidal currents. Concentrations at the creek mouth increase by as much as two orders of magnitude during strong wind events due to the presence of waves; however, large net sediment loads appear to be related to the coupled effects of waves and large tidal prisms. Waves initially mobilize sediments in the adjacent embayment but increased tidal prisms, and the associated higher velocities, are requisite for transport of this material further into the creek. Large tidal prisms may be the result of astronomically high tides or meteorologically forced tides. In Cedar Creek, the most important meteorological events affecting sedimentary processes are extra-tropical storms. This is because they occur at much higher frequencies than tropical storms and hurricanes, even though the latter are more potent and potentially could transport greater amounts of material. This study identifies the important processes controlling suspended solid transport in the broad expanses ofJuncus roemerianusdominated marsh adjacent to the large arcuate embayments prevalent along the west-central Florida marsh coast as described by Hine and Belknap (1988). The processes exerting control over sediment transport in the Cedar Creek drainage basin are similar to those documented in other marsh systems.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Estuarine, Coastal and Shelf Science, v. 41, issue 2, p. 225-248

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