Generalized Shallow Water Wave Growth from Lake George

Probably the best set of observations of wave growth in shallow water presently available has been acquired in 1996 by Young and Verhagen in Lake George, Australia. These observations were taken during nominally ideal conditions of a constant wind, in fetch-limited conditions, over water with a constant depth (wind from the North or South, along the main axis of the elongated lake). However, we found a north-south stratification in the data that Young and Verhagen ignored. This stratification suggests that the wave growth was affected by the tapering of the lake in southern-wind conditions but not in northern-wind conditions (when the upwind lake is wider). This interpretation was supported by computations with a numerical wave model. We therefore removed the southern-wind data and reanalyzed the northern wind data to reformulate the growth curves for the significant wave height and peak period. For young sea states (relatively deep and transitional water depths), we find considerably higher (by 30%)—but not longer—waves than the original authors, in agreement with a widely accepted compilation of other wave growth data. For fully developed conditions (in shallow water), our results agree well with those of the original authors.