Process Variation Across a Barred, Tidal Nearshore

by J. R. Allen, Natl Park Service/NARO, Boston, United States,
B. O. Bauer, Natl Park Service/NARO, Boston, United States,
N. P. Psuty, Natl Park Service/NARO, Boston, United States,
R. W. G. Carter, Natl Park Service/NARO, Boston, United States,



Document Type: Proceeding Paper

Part of: Coastal Sediments

Abstract:

Detailed measurements of nearshore motions and morphologic change across the inner bar-trough of a barred, tidal beach were taken at Canaveral N.S., Florida. Tidal range was <1 m and breaking wave heights of 1 meter resulted in >0.3 m of setup. There was little variation in peak spectral period of the incident waves. Low frequency (<0.08 Hz) spectral energy dominated fluid motions at low to mid-tide. There was considerable cross-shore modulation of spectral shape with first sub-harmonic dominance near the shoreline. Wave motion was standing at <0.08 Hz, progressive at higher frequencies. Mean flows at 0.15 m above the bed were largest on the bar crest and had an offshore directed component. Onshore transport of sediment is attributed to velocity skewness. Bar growth appears to have been favored by a standing edge wave (n = 3) at 0.035 Hz with an antinode over the landward slope. Cross-shore structure of the edge wave was unaffected by tidal regime, suggesting that it was topographically modulated.

Subject Headings: Tides | Breaking waves | Sediment transport | Nearshore | Motion (dynamics) | Beaches | Standing waves | Florida | United States

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