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The influence of bed friction variability due to land cover on storm-driven barrier island morphodynamics

Coastal Engineering

By:
ORCID iD , ORCID iD , ORCID iD , , and
https://doi.org/10.1016/j.coastaleng.2017.11.005

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Abstract

Variations in bed friction due to land cover type have the potential to influence morphologic change during storm events; the importance of these variations can be studied through numerical simulation and experimentation at locations with sufficient observational data to initialize realistic scenarios, evaluate model accuracy and guide interpretations. Two-dimensional in the horizontal plane (2DH) morphodynamic (XBeach) simulations were conducted to assess morphodynamic sensitivity to spatially varying bed friction at Dauphin Island, AL using hurricanes Ivan (2004) and Katrina (2005) as experimental test cases. For each storm, three bed friction scenarios were simulated: (1) a constant Chezy coefficient across land and water, (2) a constant Chezy coefficient across land and depth-dependent Chezy coefficients across water, and (3) spatially varying Chezy coefficients across land based on land use/land cover (LULC) data and depth-dependent Chezy coefficients across water. Modeled post-storm bed elevations were compared qualitatively and quantitatively with post-storm lidar data. Results showed that implementing spatially varying bed friction influenced the ability of XBeach to accurately simulate morphologic change during both storms. Accounting for frictional effects due to large-scale variations in vegetation and development reduced cross-barrier sediment transport and captured overwash and breaching more accurately. Model output from the spatially varying friction scenarios was used to examine the need for an existing sediment transport limiter, the influence of pre-storm topography and the effects of water level gradients on storm-driven morphodynamics.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The influence of bed friction variability due to land cover on storm-driven barrier island morphodynamics
Series title:
Coastal Engineering
DOI:
10.1016/j.coastaleng.2017.11.005
Volume:
132
Year Published:
2018
Language:
English
Publisher:
Elsevier
Contributing office(s):
St. Petersburg Coastal and Marine Science Center
Description:
13 p.
First page:
82
Last page:
94
Country:
United States
State:
Alabama
Other Geospatial:
Dauphin Island