Keywords
beach nourishment
groin
How to Cite
Abstract
The evolution of a beach nourishment project constructed in Long Branch, NJ was investigated using the method of empirical orthogonal functions (EOF). Most applications of EOFs on beach fill projects have focused on traditional linear fills on relatively long, straight, uninterrupted coastlines. The Long Branch project was somewhat unique in that it was designed as a feeder beach and was constructed within a groin field. EOFs were used to analyze shoreline positions and nearshore beach slopes at the site. The first three modes, determined from the shoreline position data set, explain more than ninety percent of the variation from the mean. Mode 1 and Mode 3 illustrate variations of the fill's spreading as material moved in the direction of the net littoral drift, where several shore-perpendicular structures intercepted it. One of these structures was a large outfall pipe, which was shown to have a dominant influence over the shoreline evolution. The second mode was related to seasonal or storm impacts. The EOF analysis of the beach slope data also identified modes related to the spreading of the fill (Mode 2) and seasonal impacts (Mode 1). Overall, the eigenfunctions determined from both data sets reflect the morphological changes which were observed during the field surveys.References
Aubrey, D. G. (1979). Seasonal patterns of onshore/offshore sediment movement. Journal of Geophysical Research: Oceans (1978-2012), 84(C10), 6347-6354.
Bjornsson, H., & Venegas, S. A. (1997). A manual for EOF and SVD analyses of climatic data. CCGCR Report, 97(1).
Bochev-van der Burgh, L.M., Wijnberg, K.M., Hulscher, S.J.M.H. 2009. Dune Morphology along a Nourished Coastline. Journal of Coastal Research SI 56, 292-296.
Clarke, D.J., Eliot, I.G., 1982. Description of littoral alongshore sediment movement from empirical eigenfunction analysis. Journal of the Geological Society of Australia 29, 327-341.
Dean, R.G., & Dalrymple, R. A. (2004). Coastal Processes with Engineering Applications. New York: Cambridge University Press.
Fairley, I., Davidson, M., Kingston, K., Dolphin, T. and Phillips, R. 2009. Empirical orthogonal function analysis of shoreline changes behind two different designs of detached breakwaters. Coastal Engineering, 56, (11-12), 1097-1108.
Hotelling, H., 1933. Analysis of a complex of statistical variables into principle components. Journal of Educational Psychology, 24: 417-441, 498-520.
Kroon, A., Larson, M., Moller, I., Yokoi, H., Rozynski, G., Cox, J., Larroude, P., 2008. Statistical analysis of coastal morphological data sets over seasonal to decadal time scales. Coastal Engineering 55, 581-600.
Larson, M., Hanson, H., Kraus, N.C., Newe, J. 1999. Short- and Long-Term Responses of Beach Fills Determined by EOF Analysis. Journal of Waterway, Port Coastal, and Ocean Engineering 25 (6), 285-293.
Miller, J.K., A.M Mahon and T.O. Herrington, 2009. "Development of the Stevens Dynamic Underwater Coastal Surveying (DUCKS) System." Davidson Laboratory Technical Report, Coastal Protection Technical Assistance Service.
Miller, J.K., and T.O. Herrington, 2008. "Long Branch Alternate Fill Placement Monitoring Plan, Long Branch, New Jersey" Davidson Laboratory Technical Report, Coastal Protection Technical Assistance Service.
Munoz-Perez, J.J., Medina, R., Tejedor, B. 2001. Evolution of longshore beach contour lines determined by the E.O.F. method. Scientia Marina 65 (4), 393-402.
Munoz-Perez, J.J., Medina, R. 2010. Comparison of long-, medium-, and short-term variations of beach profiles with and without geological control. Coastal Engineering 57, 241-251.
Pearson, K., 1901. On lines and planes of closest fit to systems of points in space. Philosophical Magazine 6 (2), 559-572.
Winant, C.D., Inman, D.L., Nordstron, C.E., 1975. Description of seasonal beach changes using empirical eigenfunctions. Journal of Geophysical Research 80 (15), 1979-1986.