Testing model parameters for wave‐induced dune erosion using observations from Hurricane Sandy

Models of dune erosion depend on a set of assumptions that dictate the predicted evolution of dunes throughout the duration of a storm. Lidar observations made before and after Hurricane Sandy at over 800 profiles with diverse dune elevations, widths, and volumes are used to quantify specific dune e...

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Bibliographic Details
Published in:Geophysical research letters 2017-01, Vol.44 (2), p.937-945
Main Authors: Overbeck, J. R., Long, J. W., Stockdon, H. F.
Format: Article
Language:English
Subjects:
Beach erosion
Beach slope
Beaches
Coasts
collision
Decision making
dune erosion
Dunes
Duration
Erosion
Erosion models
Evolution
Foreshore
Hurricane Sandy
Hurricanes
Lidar
Mathematical models
Meteorology
Migration
Parameters
Profiles
Slope
Slopes
Soil erosion
Storms
Testing
Trajectories
Vulnerability
wave impact
wave runup
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Summary:Models of dune erosion depend on a set of assumptions that dictate the predicted evolution of dunes throughout the duration of a storm. Lidar observations made before and after Hurricane Sandy at over 800 profiles with diverse dune elevations, widths, and volumes are used to quantify specific dune erosion model parameters including the dune face slope, which controls dune avalanching, and the trajectory of the dune toe, which controls dune migration. Wave‐impact models of dune erosion assume a vertical dune face and erosion of the dune toe along the foreshore beach slope. Observations presented here show that these assumptions are not always valid and require additional testing if these models are to be used to predict coastal vulnerability for decision‐making purposes. Observed dune face slopes steepened by 43% yet did not become vertical faces, and only 50% of the dunes evolved along a trajectory similar to the foreshore beach slope. Observations also indicate that dune crests were lowered during dune erosion. Moreover, analysis showed a correspondence between dune lowering and narrower beaches, smaller dune volumes, and/or longer wave impact. Key Points Observations are used to quantify the accuracy of assumptions used in dune erosion models Dune vulnerability to overwash is observed to increase due to dune erosion Initial beach width, dune volume, and wave‐impact hours contribute to dune erosion variability
ISSN:0094-8276
1944-8007
DOI:10.1002/2016GL071991