Although waves come in all sizes, they all have essentially the same characteristics. Wave height is measured vertically from the wave's crest to its trough. Wave period is the time it takes a wave, trough to trough or crest to crest, to travel the distance equal to one wave length. Waves, with a short period, are moving very quickly. A wave breaks when the depth of the water is four-thirds its height.
Waves break against the shore releasing varying amounts of energy.
The amount is dependent upon the slope of the bottom and the wave height. The amount of energy contained in a wave is directly proportional to its height. Therefore, the higher the wave, the more energy it contains. This uncontrolled energy continuously erodes material away from the shore transporting sand along the shoreline and cutting away at bluffs. For several reasons, however, wave energy arriving at the shoreline is not constant.