Equilibrium coastal profiles: I. Review and synthesis

  • Gao Shu
  • Michael Collins


Applicability of the coastal equilibrium concept depends upon proof of the existence of equilibrium. The present study demonstrates that, on the basis of the sediment continuity equation, three types of equilibrium are possible. Type I equilibrium requires that instantaneous sediment transport rates in both longshore and cross-shore directions are small, representing a final stage of erosion in response to natural processes. Type II equilibrium is reached if there are no variations in the net sediment transport rate in the longshore directions (i.e. zero cross-shore sediment transport). Such a situation occurs if the coastline is straight and there are no alongshore variations in hydrodynamic (i.e. wave and tidal) conditions. Type III equilibrium occurs when there are variations in longshore transport rates but the magnitude of instantaneous transport rate in the longshore direction is small compared with that in the cross-shore directions. In this case, the coastal profile is characterised by parallel advancement or retreat. Disequilibrium occurs if these conditions are not satisfied. Hence, prior to the selection of methods to determine the equilibrium coastal profile and the response time, the type of equilibrium must be identified.

Key words

coastal profile equilibrium sediment movement 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bruun, P., 1954. Coast erosion and the development of beach profiles. Beach Erosion Board, Technical Memo No.44, 79 p.Google Scholar
  2. Cornaglia, P., 1898. On beaches.In: Fisher, J. S. and Dolan, R. (editors), 1977, Beach Processes and Coastal Hydrodynamics, Dowden, Hutchingson and Ross, Stroudsburg. p. 11–26.Google Scholar
  3. Cornish, V., 1898. On sea beaches and sand banks.Geogr. J. 11: 528–559, 628–647.CrossRefGoogle Scholar
  4. Dally, W. R., Dean, R. G., 1984. Suspended sediment transport and beach profile evolution.J. Waterway, Port, Coastal Ocean Eng., ASCE 110: 15–33.CrossRefGoogle Scholar
  5. Dean, R. G., 1977. Equilibrium beach profiles: U.S. Atlantic and Gulf Coasts. Department of Civil Engineering, Ocean Engineering Report No. 12, University of Delaware, 45 p.Google Scholar
  6. Dean, R. G., 1991. Equilibrium beach profiles: characteristics and application.J. Coast. Res. 7: 53–84.Google Scholar
  7. Dean, R. G., Healy, T. R., Dommerholt, A. P., 1993. A “blind-folded” test of equilibrium beach profile concepts with New Zealand data.Mar. Geol. 109: 253–266.CrossRefGoogle Scholar
  8. Fennemen, N. M., 1902. Development of the profile of equilibrium of the subaqueous shore terrace.J. Geol. 10: 353–369.Google Scholar
  9. Fredsoe, J., Deigaard, R., 1992. Mechanics of Coastal Sediment Transport. World Scientific, Singapore, 369 p.Google Scholar
  10. Greenwood, B., Miller, P. R., 1984. Sediment flux and equilibrium slopes in a barred nearshore.Mar. Geol. 60: 79–98CrossRefGoogle Scholar
  11. Hayes, M.O., 1967. Relationship between coastal climate and bottom sediment on the inner continental shelf.Mar. Geol. 5: 111–132.CrossRefGoogle Scholar
  12. Hsu, J. R. C., Silvester, R., Xia, Y.M., 1989. Generalities on static equilibrium bays.Coast. Eng 12: 353–369.CrossRefGoogle Scholar
  13. Johnson, D. W., 1919. Shore Processes and Shoreline Development. John Wiley, New York, 584 p.Google Scholar
  14. King, C. A. M., 1972. Beaches and Coasts (2nd edition). Edward Arnold, London, 570 p.Google Scholar
  15. Leont'ev, I. O., 1985. Sediment transport and beach equilibrium profile.Coast. Eng. 9: 277–291.CrossRefGoogle Scholar
  16. Liu, J. T., Zarillo, G. A., 1989. Distribution of grain sizes across a transgressive shoreface.Mar. Geol. 87: 121–136.CrossRefGoogle Scholar
  17. Massel, S. R., 1989. Hydrodynamics of Coastal Zones. Elsevier, Amsterdam, 336 p.Google Scholar
  18. Musielak, S., 1978. Littoral processes in the swash zone.Oceanologia,8: 5–56. (in Polish, with English abstract).Google Scholar
  19. Nairn, R. B., Southgate, H. N., 1993. Deterministic profile modelling of nearshore processes. Part II: Sediment transport and beach profile development.Coast. Eng. 19: 57–96.CrossRefGoogle Scholar
  20. Nummedal, D., Sonnenfeld, D. L., Taylor, K., 1984. Sediment transport and morphology at the surf zone of Presque Isle, Lake Erie, Pennsylvania.Mar. Geol. 60: 99–122.CrossRefGoogle Scholar
  21. Powell, K. A., 1986. The Hydraulic Behaviour of Shingle Beaches under Regular Waves of Normal Incidence. Unpublished Ph.D. Thesis, University of Southampton, 359 p.Google Scholar
  22. Silvester, R., 1974. Coastal Engineering (Vol.2). Elsevier, Amsterdam, 338 p.Google Scholar
  23. Southgate, H. N., Nairn, R. B., 1993. Deterministic profile modelling of nearshore processes. Part I: Waves and Currents.Coast. Eng. 19: 27–56.CrossRefGoogle Scholar
  24. Sunamura, T., 1984. Quantitative predictions of beach-face slopes.Bull. Geol.Soc. Amer. 95: 242–245.CrossRefGoogle Scholar
  25. Wright, L. D., 1995. Morphodynamics of Inner Continental Shelves. CRC Press, Boca Raton, 241 p.Google Scholar
  26. Zenkovich, V. P., 1967. Processes of Coastal Development (English edition). Oliver and Boyd, Edinburgh, 738 p.Google Scholar

Copyright information

© Science Press 1998

Authors and Affiliations

  • Gao Shu
    • 1
  • Michael Collins
    • 2
  1. 1.Institute of OceanologyChinese Academy of SciencesQingdao
  2. 2.Department of OceanographyThe UniversitySouthamptonUK

Personalised recommendations