HR: 15:10h
AN: H33L-07    [Abstracts]
TI: Simplified Marsh Platform Flow Model of Flood and Ebb Informed By Platform Length Scale and Biomass
AU: * Howell, S M
EM: s.m.howell@vanderbilt.edu
AF: Vanderbilt University Department of Earth and Environmental Sciences, 2301 Vanderbilt Place Station B 35-1805, Nashville, TN 37235, United States
AU: Furbish, D J
EM: david.j.furbish@vanderbilt.edu
AF: Vanderbilt University Department of Earth and Environmental Sciences, 2301 Vanderbilt Place Station B 35-1805, Nashville, TN 37235, United States
AU: Mudd, S M
EM: smudd@staffmail.ed.ac.uk
AF: School of GeoSciences University of Edinburgh Grant Institute, The King's Buildings, Edinburgh, EH9 3JW, United Kingdom
AB: Tidal salt marsh ecosystems are maintained by macrophytes that regulate platform elevation by inorganic and organic sedimentation, as well as modify the flow within the canopy. In an effort to understand and simplify the ecological and physical interactions on tidal salt marsh platforms, here we explore a two-dimensional hydrodynamic field that incorporates velocity solved as a function of the drag coefficient and Reynolds number. The flow model, based on depth-integrated conservation of mass and momentum equations, is governed by the assumption of a balance between the drag force generated by macrophyte stems and the gravitational force due to the slope of the water surface. The form drag exerted by a single infinite cylinder is parameterized through a drag coefficient at transitional Reynolds numbers. At large scales the flood and ebb can be described using diffusion-like equations; however, at smaller scales a bathtub approximation is more appropriate. Here we quantify the lengths scales and fractional volume of the flow domain occupied by plants appropriate for a bathtub- like flooding description. Because the rate of platform flow on short length scales is a function of biomass, flooding translates to frequency and duration of inundation with elevation. The resulting simplified marsh platform flow and mapping of mean high tide can be used directly with a zero-dimensional model for biomass production as a function of elevation.
DE: 0442 Estuarine and nearshore processes (4235)
DE: 1813 Eco-hydrology
DE: 1824 Geomorphology: general (1625)
DE: 1847 Modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting