Cross-shore sediment transport on a naturally barred beach
By: Randall T. Humiston
Publisher: Naval Postgraduate School; Available from the National Technical Information Service
Published: 1993
Place of publication: Monterey, Calif; Springfield, Va
Language: eng
Number of pages: 36
Description: Bailard's sediment transport model (1981) is evaluated using field data obtained on a naturally barred beach. Principal field measurements consist of a cross-shore array of bi-directional current meters spanning the surf zone and daily bathymetic surveys. The model predicts bed and suspended Load transport separately based on various velocity moments. The velocities are partitioned into mean currents, long waves (< 0.05 Hz) and short waves (.0.05 Hz) to determine their relative importance to the transport. Velocity moments are computed over 90 minutes intervals to resolve tidal fluctuations. Finally, predicted transport rates are integrated and compared with daily cross-shore bathymetric profiles (Averaged over a 400m length of beach). Results indicate the suspended load was consistently greater than bed load as much as an order of magnitude during episodes of large incident waves, owing to the slow fall velocity (2cm/s) of the fine grain sand within the surf zone. The contribution by the mean current, long and short waves to the cross-shore transport were of the same order. Variance of transport during all stages of tide and over a range of incident waves were consistently greater in the vicinity of the bar and trough than seaward of the bar and on the beach face. Tidal signatures were apparent in all modes of transport. The model appeared to under-predict measured bathymetry during low-energy periods and over-predict during high-energy conditions. However, the model does correctly predict the first order of movement of the bar.
Notes: Thesis advisor(s): Thornton, Edward B.

"March 1993."

Thesis (M.S. in Physical Oceanography and Meteorology) Naval Postgraduate School, March 1993.

Includes bibliographical references.

Approved for public release; distribution unlimited.

Also available online.

Mode of access: World Wide Web.

System requirements: Adobe Acrobat Reader.

US Navy (USN) author.