Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Sediment transport in the coastal environment /
Author Madsen, Ole Secher. ; Grant, William D.
Other Authors
Author Title of a Work
no. 209. Ralph M. Parsons Laboratory for Water Resources and Hydrodynamics.Research report
R76-7. Massachusetts Institute of Technology.
Publisher Ralph M. Parsons Laboratory for Water Resources and Hydrodynamics, Dept. of Civil Engineering, Massachusetts Institute of Technology,
Year Published 1976
Report Number OSP 81620
OCLC Number 02234779
Subjects Sediment transport. ; Coast changes.
Additional Subjects Sediment transport ; Coast changes
Library Call Number Additional Info Location Last
ESBD  1MA MIT NHEERL/WED Library/Corvallis,OR 01/01/1988
ESBD  100 MA MIT 209 NHEERL/WED Library/Corvallis,OR 03/10/2017
Collation xiii, 105 pages : illustrations ; 28 cm.
"January 1976." "OSP 81620." Includes bibliographical references (pages 97-101). Prepared under the support of Dames and Moore, Consultants in the Environmental and Applied Earth Sciences, Cranford, New Jersey, through funds provided by New Jersey Public Service Electric and Gas Company, Newark, New Jersey.
Contents Notes
The subject of sediment transport in the coastal zone is investigated and the answers to some of the basic questions of sediment transport in unsteady, oscillatory flow are presented. By adopting Jonsson's (1966) results for the bottom shear stress associated with a simple wave motion, it is shown that Shield's criterion for the initiation of sediment movement on a flat bed holds in unsteady as well as steady flow. A simplified analysis as well as experimental data show the side effects associated with the experimental procedure in which a tray containing sediment is oscillated in still water is generally insignificant and is, therefore, a valid procedure for studying certain aspects of wave sediment interaction. Also, Shields Parameter is identified as the physically important parameter quantifying the fluid sediment interaction. An empirical relationship between a non-dimensional average sediment transport rate and Shields Parameter is found by reanalyzing the experimental data on the rate of sediment transport in oscillatory flow obtained by Einstein and co-workers at Berkeley. This relationship is similar to the Einstein-Brown sediment transport relationship in unidirectional, steady flow. By generalizing Jonsson's expression for the bottom shear stress associated with a sinusoidal wave motion, it is shown that the empirical sediment transport relationship may be derived from a quasi steady application of the Einstein-Brown sediment transport relationship. Also, it is demonstrated that the empirical relationship obtained using a friction factor based on grain roughness is capable of predicting sediment transport rates observed in experiments where bed forms were present. The general application of the derived sediment transport relationship for predicting net rates of sediment transport in the presence of second order effects such as bottom slope, wave asymmetry, mass transport currents and coastal currents is discussed. This discussion serves also to identify needed areas for future research. It is concluded that only the case of a small amplitude wave and a steady current seems to be understood to the extent that it is reasonable to evaluate the resulting sediment transport with any degree of confidence. Fortunately, this is a rather important situation in most offshore regions. A general numerical model is developed for the sediment transport and topographical changes resulting from spatially varying wave and current conditions. A simple numerical example of the evaluation of the topographical changes in the vicinity of the tip of a long straight breakwater is presented for periodic waves normally incident on the breakwater and a current parallel to the breakwater. This numerical example is chosen to resemble rather severe conditions for the Atlantic Generating Station (AGS) site with a maximum orbital wave velocity of 3.2 ft/sec (1 m/sec) and a current velocity 0.5 ft/sec (.15 m/sec). The results are.presented in a topographical relief map showing areas of scour and accretion of the order 0.78 inches/day (2 cm/day) at a maximum. Although the results of the example are somewhat more qualitative than-quantitative, it is felt that they provide a representative picture of the expected bottom changes in the vicinity of the AGS.