Study of Wind Waves in the Gulf Intracoastal Waterway at Aransas National Wildlife Refuge

Abstract

This study describes a field experiment on wind waves in the Gulf Intracoastal Waterway. Wind-wave height and period were measured at the Aransas National Wildlife Refuge in Texas and compared to hindcast results generated by the wind-wave model for restricted fetches in the Automated Coastal Engineering System. The comparisons showed that the present technology did not predict the measurements well. The restricted fetch method showed a tendency to overpredict waves when the wind was blowing along the channel and underpredict waves when the wind was blowing across the channel. The poor performance of the restricted fetch model in long, narrow channels was attributed to the measured data being far outside the bounds of the data used to develop the model (fetch width-to-length ratio, as well as wave height and period). It was shown that wave damping could reduce wave heights for along-channel winds. Analysis of an elliptical fetch suggested that fetch width-to-length ratio is an important variable. Because this parameter is not included in the wave-prediction equations, the formulas should only be applied to water bodies similar in width-to-length ratio to those used to develop the model.