ABSTRACT

Shuster, R.; Sherman, D.J.; Lorang, M.S.; Ellis, J.T., and Hopf, F., 2020. Erosive potential of recreational boat wakes. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1279–1283. Coconut Creek (Florida), ISSN 0749-0208.

Recreational boat wakes are important sources of erosive energy in many sheltered coastal and estuarine environments. The energy content of a wake depends on boat speed, length, hull-shape and displacement and the energy delivered to an adjacent shoreline is also a function of the distance traveled by the wake. In this study that was conducted in the estuarine waters of Georgiana Slough, which is a distributory channel of the Sacramento River in California, basic geometries and speeds of common recreational boats were recorded along with the height and period of the wakes they generated. A site was instrumented with a motion-sensing video camera and pressure transducer to record boat passages and resulting wakes. Regression analysis using a curated data set produced a coefficient of determination of 0.87 linking index wave energy and boat length cubed. These results suggest that the length of a boat traveling at typical cruising speeds is a useful predictor of wake energy when a passage is within about 30 m of the shoreline. Further research is required to quantify the effects of greater distances on wake attenuation. This method could be used to monitor boat traffic in sensitive coastal environments, assess possible erosion risk from boat wakes, and inform management responses.

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