Evaluation of Methods for Estimating Wind Wave Growth on Narrow Irregular Fetches

The purpose of this study was to compare three different methods for generating wave heights and periods on a narrow irregular fetch with data from a typical Alaskan site. Kodiak, Alaska, was selected because concurrent wind and wave measurements were available for a period of 3 years. Based on wind direction blowing down the narrow fetch to the wave buoy, 79 cases for comparison were chosen. Swell was removed from the buoy data so that only wind waves generated down the narrow fetch were compared. Comparisons were made against the JONSWAP wave growth equations as found in the Shore Protection Manual (1984) or Water Levels and Wave Heights for Coastal Engineering Design (1989), NARFET, a wind-wave generation on restricted fetches analytical model, and STWAVE, a gridded steady-state spectral model. Results of the study showed that STWAVE matched the buoy wave heights within 0.1 ft based on the mean and that NARFET matched the buoy wave periods within 0.2 sec, based on the mean. This limited study suggests that STWAVE and NARFET, respectively, should be used for determining wave heights and periods for narrow irregular fetches. arrow fetch, Restricted fetch, Numerical modeling, STWAVE model, Reservoir waves, Wind-wave generation.