Waves and Rip Currents on a Caribbean Pocket Beach, Jamaica

Abstract

Using relatively simple methods, the wave and current patterns in Engine Head Bay, Jamaica, a remote arcuate bay exposed to incident swell, have been investigated. A wave refraction program shows that convergence of incident waves occurs at the mouth of the Bay creating relatively large, and spatially varying, wave heights. A one-week field programme in the Bay used a fixed pressure sensor to monitor incident wave conditions, and a combination of float and dye tracking to describe and quantify the currents. A persistent central rip current was found, with a maximum strength of 65 cm s ^-1. The variation of rip current strength was found to be directly related to variations of incident wave height over periods of a few minutes. This is consistent with the observations of rip currents by Mackenzie (1958) but is inconsistent with the rip currents on an open coast described by Shepard et al. (1950), perhaps indicating that long wave motion on the scale of the bay may determine rip current strength. The results of this project indicate what can be achieved in a remote environment where manpower skills and resources are limited.