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 . Th e 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.