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Coastal Hydrology and Salt Marshes
Our work is aimed at clarifying certain hydro-geomorphic processes in coastal areas. This has recently involved combining theory, a scaled physical model and novel visualization techniques to examine tidally induced groundwater circulation in an unconfined aquifer. We are also focusing on how salt marshes respond to sea-level changes. This work involves developing a coupled hydrodynamic-biologic model to characterize flow, sedimentation and biomass production on marsh platforms, and is in collaboration with Jim Morris (South Carolina), Donald Cahoon (US Geological Survey) and Bob Christian (East Carolina).
Pamlico Sound area, North Carolina.
Response of Coastal Salt Marshes to Sea-Level Change
Our current work, funded by NOAA and led by Jim Morris, is aimed at forecasting effects of sea-level rise on coastal ecosystems in Pamlico Sound, North Carolina. This North Carolina project combines field measurements of sedimentation rates and responses of vegetation to inundation period with numerical modeling of the interaction between vegetation structure and flood-ebb hydrodynamics. This work is particularly important in light of predictions of accelerated sea-level rise associated with global warming.
Mudd, S. M., Fagherazzi, S., Morris, J. T. and Furbish, D. J. 2004. Flow, sedimentation, and biomass production on a vegetated salt marsh: Toward a predictive model of marsh morphologic and ecologic evolution. (in press)
Fagherazzi, S., Gabet, E. J. and Furbish, D. J. 2004. The effect of bidirectional flow on tidal channel planforms. Earth Surface Processes and Landforms, 29, 295-309.
Fagherazzi, S. and Furbish, D. J. 2001. On the shape and widening of salt-marsh creeks. Journal of Geophysical Research, 106, C1 , 991-1005.
Time-averaged velocity field (vectors) and standard deviation of velocity magnitude (contous) revealed by particle imaging velocimetry of fluid within Hele-Shaw cell scaled to natural conditions (Mango et al., 2004. Geology, 32, 233-236).
Tidally Driven Groundwater Circulation
Our geometrically and dynamically scaled Hele-Shaw cell experiments reveal a tidally driven time-averaged circulation beneath the tidal zone. The presence of this circulation suggests that a significant part of submarine groundwater discharge near this zone represents cycled seawater rather than freshwater input to the ocean.
Mango, A. J., Schmeeckle, M. W. and Furbish, D. J. 2004. Tidally induced groundwater circulation in an unconfined aquifer modeled with a Hele-Shaw cell. Geology, 32, 233-236.
Dillon, K. S., Corbett, D. R., Chanton, J. P., Burnett, W. C. and Furbish, D. J. 1999. The use of sulfur hexafluoride (SF6) as a tracer of septic tank effluent in the Florida Keys. Journal of Hydrology, 220, 129-140.
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