词条 | Coastal sediment transport |
释义 |
HistoryIn the mid-1970s a significant amount of attention was paid to coastal sediment transport. In part, due to the National Sea Grant College Program and the U.S. Congress Mandated Sea Grant Act of 1976. One of the research areas included "the development and the experimental verification of hydrodynamic laws governing the transport of marine sediments in the flow fields occurring in coastal waters." [7] From this request for research, the Office of Sea Grant reviewed, accepted, and funded the Nearshore Sediment Transport Study (NSTS). Due to unforeseen complications the NSTS conducted only two major field experiments and a validation experiment.[7] This was a significant contribution to the field of coastal sediment transport and helped initialize a great deal of future research. Glossary
Beach profile measurementsA variety of measurements are used to determine the beach profile, sediment grain size, and various other important parameters to determine what is influencing coastal sediment transport. Below are a few of the multitude. Coastal research amphibious buggy (CRAB)A three-wheeled vehicle deployed at the beach to measure the beach profile. (more information can be found at http://frf.usace.army.mil/vehicles2.stm) Emory beach profile measurementIn order to determine what the profile of a beach looks like, one method for determination is the Emory Beach Profiling Method. Initiating a benchmark, the researcher establishes a control point to start the surveys at. Typically this is far enough away from the swash zone that large changes in elevation will not occur during the sampling time. Once the initial benchmark is established, the researcher will take the Emory sampling device and measure the change in elevation over the distance the device is covering. Then, they will pick up the device and move it to the end point of their last survey, and so on. Until they reach the shoreline. Typically this is done during neap tide (see Tide for more information on neap tide). Grain size determinationSince the sand grain diameters can vary throughout the entire beach the median grain size is used to determine sediment fall velocity. Determining sediment fall velocity allows the determination of what sediment is left where...[3] Human modifications
ModelsModels for the prediction of sediment transport in coastal regions have been used since the mid 1970s.[4] Some transport models are:
References1. ^1 2 Komar, Paul D. Crc Handbook of Coastal Processes and Erosion. Crc Series in Marine Science. Boca Raton, Fla.: CRC Press, 1983. Print. {{Sediment transport}}2. ^1 2 3 4 Bird, E. C. F. Coasts. An Introduction to Systematic Geomorphology,. Cambridge, Mass.,: M.I.T. Press, 1969. Print. 3. ^1 Dean, Robert G., and Robert A. Dalrymple. Coastal Processes : With Engineering Applications. Cambridge, UK New York: Cambridge University Press, 2002. Print. 4. ^1 2 Seymour, Richard J. Nearshore Sediment Transport. New York ; London: Plenum Press, 1989. Print. 5. ^Dalrymple, R.A., Prediction of Storm/Normal Beach Profiles, Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, 118, 2, 193-200, 1992. 7 : Fluid mechanics|Geomorphology|Sedimentology|Hydrology|Physical geography|Deposition (geology)|Coastal engineering |
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