Rob A. Walker, David R. Basco


A new coastal storm-strength parameter, the Coastal Storm Impulse (COSI) parameter, was introduced at the ICCE 2006 (San Diego) and further discussed at the ICCE 2008 (Hamburg). COSI is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. Both tropical storms (hurricanes) and extra-tropical storms (northeasters) can produce similar COSI parameters that range from 0.69*10^6 N-m/hr to 49.72*10^6 n-m/hr with lognormal distribution. Potential implications of such a storm classification system include the evaluation of coastal structures and coastal infrastructure, as well as providing a universal storm strength indicator that is directly tied to coastal physical parameters and not limited to wind speed. This paper explores the application of COSI to predict coastal erosion along the sub-aerial ocean beach in Duck, North Carolina on the east coast of the United States. Data for the 10-year study period (1994 to 2003) has been analyzed to produce 249 storms for study of coastal erosion. When profile response to coastal storms was assessed through a pre- and post-storm volumetric determination, mixed results showing both erosion and accretion were observed. The paper also explores the possible explanations and implications of these findings.


coastal storm; beach erosion; storm surge; momentum; impulse


Basco, D.R., and Klentzman, C. 2006. On the Classification of Coastal Storms Using Principles of Momentum Conservation, Proceedings, ICCE 2006, San Diego, ASCE, NY, Vol 2, pp. 1407-1419.

Basco, Mahmoudpour and Kelentzman. 2008. Statistical Analysis of the Coastal Storm Impulse (COSI) Scale at the Corps of Engineers, FRF, Duck NC, Proceedings, ICCE 2008, Hamburg, ASCE, NY, Vol. 6, 4134-4142.

Dean, R.G. 1973. Heuristic Models of Sand Transport in the Surf Zone, Proceedings, Conference on Engineering Dynamics in the Surf Zone, Sydney, Australia, 208-214.

Dolan, R, Hayden, D., Bosserman, K., Lisle, L. 1987. Frequency and Magnitude Data on Coastal Storms, Journal of Coastal Research, vol. 3, no. 2. Charlottesville, VA, pp. 245-247.

Dolan, R., Lins, H., and Hayden, B. 1988. Mid-Atlantic Coastal Storms, Journal of Coastal Research, vol. 4 no. 3. Charlottesville, VA, pp. 417-433.

Hughes, S.A. 2004. Wave Momentum Flux Parameter: a Descriptor for Near Shore Waves, Coastal Engineering, vol. 51. Elsevier, pp. 1067-1084.

Kamphuis, W. 2010. Introduction to Coastal Engineering and Management, World Scientific, Inc., NJ, 2nd Edition.

Klentzman, C. 2007. Using Principles of Momentum Conservation to Develop Coastal Strom Impulse Scale (COSI), Unpublished, Ph.D. Dissertation, Old Dominion University, Norfolk, VA.

Kraus, N.C., M. Larson and D.L. Kriebel. 1991. Evaluation of Beach Erosion and Accretion Predictors, Proceedings, Coastal Sediments 1991, Seattle, ASCE, Seattle, 572-587.

Miller, J.K., Livermont, E. 2008. A Predictive Index for Wave and Storm Surge Induced Erosion, Proceedings, 31st Coastal Engineering Conference, ASCE, NY, pp 561-572.

Munger, S., and Kraus, N.C. 2010. Frequency of Extreme Storms Based on Beach Erosion at Northern Assateague Island, Maryland, Shore & Beach, Vol.78, No.2. pp. 3-11.

Sallenger, A.H., Jr. 2000. Storm impact scale for barrier islands, Journal of Coastal Research, vol. 16, no. 3. West Palm Beach, pp. 890-895.

Seymour, R.J., Strange, R.R., III, Cayan, R., Nathan, R.A. 1984. Influence of El Ninos on California's Wave Climate, Proceedings, 19th

The Organizing Committee. 1992. The Acqua Alta in Venice, Oct 4-7, 1992, Proceedings, International Conference on Coastal Engineering, ASCE, NY, vol 3.International Conf. on Coastal Engineering, ASCE, NY, Vol 1, pp 577-592.

Wright, L.D. and A.D. Short. 1984. Morphodynamic Variability of Surf Zones and Beaches, MarineGeology, Vol 56, 93-118.

You, Z.-J. and Lord, D. 2008. Influence of the El Nino-Southern Oscillation on NSW Coastal Storm Severity, Journal of Coastal Research, vol 24 Sp No.2, pp203-207.

Qi, H., Cai, F., Lei, G., Cao, H., and Shi, F. 2010. The Response of Three Beach Types to Tropical Storms in South China, Marine Geology, accepted for publication. June.

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