Coastal engineering

Coastal engineering is a branch of civil engineering concerned with the specific demands posed by constructing at or near the coast, as well as the development of the coast itself.

Wave attack on Ilfracombe's sea walls during a storm.

The hydrodynamic impact of especially waves, tides, storm surges and tsunamis and (often) the harsh environment of salt seawater are typical challenges for the coastal engineer – as are the morphodynamic changes of the coastal topography, caused both by the autonomous development of the system and man-made changes. The areas of interest in coastal engineering include the coasts of the oceans, seas, marginal seas, estuaries and big lakes.

Besides the design, building and maintenance of coastal structures, coastal engineers are often interdisciplinary involved in integrated coastal zone management, also because of their specific knowledge of the hydro- and morphodynamics of the coastal system. This may include providing input and technology for e.g. environmental impact assessment, port development, strategies for coastal defense, land reclamation, offshore wind farms and other energy-production facilities, etc.

Specific challenges
Beach nourishment at the Dutch coast.

The coastal environment produces challenges specific for this branch of engineering: waves, storm surges, tides, tsunamis, sea level changes, sea water and the marine ecosystem.

Most often, in coastal engineering projects there is a need for metocean conditions: local wind and wave climate, as well as statistics for and information on other hydrodynamic quantities of interest. Also, bathymetry and morphological changes are of direct interest. In case of studies of sediment transport and morphological changes, relevant properties of the sea bed sediments, water and ecosystem properties are needed.

Long and short waves
Classification of the spectrum of ocean waves according to wave period, by Walter Munk (1950).[1]

The occurrence of wave phenomena – like sea waves, swell, tides and tsunamis – require engineering knowledge of their physics, as well as models: both numerical models and physical models. The practices in present-day coastal engineering are more-and-more based on models verified and validated by experimental data.

Apart from the wave transformations themselves, for the waves coming from deep water into the shallow coastal waters and surf zone, the effects of the waves are important. These effects include:

Underwater construction
Main article: Underwater construction

Coastal engineering takes place at or near the interface between land and water. Consequently a significant part of coastal engineering involves underwater construction, particularly for foundations. Breakwaters, sea walls, harbour structures like jetties, wharves and docks, bridges, tunnels, outfalls and causeways usually involve underwater work.

Sustainability and soft engineering

In recent decades, coastal engineers have favored non-structural solutions, which avoid adverse impacts that are typically cause by structures, such as sea walls, bulkheads, jetties, etc. These solutions include beach nourishment, marsh restoration/creation, and habitat restoration. More recently, beneficial use of dredge material, which utilizes material dredged for navigation maintenance to nourish beaches and restore wetlands. Beneficial use is also employed to increase the elevation of marsh platforms in an attempt to adapt to sea level rise.

Regional sediment management has also become a focus strategy for coastal practitioners. This essentially uses nearshore sediment sources and knowledge of coastal morphology to identify which accretional features can be harvested to bolster erosional areas, understanding the harvested material will continue to accumulate. A common regional sediment management option is to dredge ebb and flood shoals to nourish beaches.

Both beneficial use and regional sediment management recognizes the scarcity of material resources offshore and upland.

See also

Notes
  1. Munk, W.H. (1950), "Origin and generation of waves", Proceedings 1st International Conference on Coastal Engineering, Long Beach, California: ASCE, pp. 1–4

References
  • Dean, R.G.; Dalrymple, R.A. (2004), Coastal Processes with Engineering Applications, Cambridge University Press, Bibcode:2004cpea.book.....D, ISBN 9780521602754
  • Hughes, S.A. (1993), Physical Models and Laboratory Techniques in Coastal Engineering, Advanced series on ocean engineering, World Scientific, ISBN 9789810215415
  • Kamphuis, J.W. (2010), Introduction to Coastal Engineering and Management, Advanced series on ocean engineering, World Scientific, ISBN 9789812834843
  • Kraus, N.C. (1996), History and Heritage of Coastal Engineering, American Society of Civil Engineers, ISBN 9780784474143
  • Sorensen, R. (2013), Basic Coastal Engineering, Springer, ISBN 9781475726657
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