thumbnail

A circulation modeling approach for evaluating the conditions for shoreline instabilities

By:
,
DOI: 10.1061/40926(239)25

Links

Abstract

Analytical models predict the growth (instability) of shoreline salients when deep-water waves approach the coast from highly oblique angles, contrary to classical shoreline change models in which shoreline salients can only dissipate. Using the process-based wave, circulation, and sediment transport model Delft3D, we test this prediction for simulated bathymetric and wave characteristics approximating the open-ocean conditions at Duck, North Carolina. We consider two cases: a uniform coast with a varying wave approach angle, and a bathymetry with coastal salients and a single high-angle boundary wave condition. Incident wave conditions include a swell case with no wind and a wind-wave case with active local wave regeneration by wind. The uniform-coast tests predict transport maxima at oblique wave angles for both wave cases, indicating the potential for shoreline instabilities, similar to the analytical models. However, the critical angle for instability is much higher in the wind-wave case. Our tests with coastal salients agree with previous findings that a minimum salient length scale may be required for the instability effect to be active. Here, a salient with a longshore scale of 4 km results in transport divergence (erosion; no instability) at the salient crest while an 8 km salient results in transport convergence (accretion; instability) at the crest.

Geospatial Extents

Additional Publication Details

Publication type:
Conference Paper
Publication Subtype:
Conference Paper
Title:
A circulation modeling approach for evaluating the conditions for shoreline instabilities
ISBN:
0784409269; 9780784409268
DOI:
10.1061/40926(239)25
Year Published:
2007
Language:
English
Publisher:
American Society of Civil Engineers
Contributing office(s):
Coastal and Marine Geology Program
Description:
14 p.
Larger Work Type:
Book
Larger Work Subtype:
Conference publication
First page:
327
Last page:
340
Number of Pages:
14
Conference Title:
6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes
Conference Location:
New Orleans, LA
Country:
United States
State:
North Carolina
City:
Duck