When wind blows over the water creates a frictional movement of water at the surface producing traveling surface waves. If and when these waves are large enough to break (due to high wind energy or shoaling), their energy flux and dispersion is transferred to the water column. They are confined to the surface layer and do not cause significant displacement in the water column. Short surface waves cause water particles to move in a vertical circular path due to gravity. Waves with a period of between 0.3 and 30 seconds (3 Hz to 0.03 Hz) are called gravity waves. Shorter waves are also affected by surface tension and are called gravity–capillary waves. In Lake Ontario the highest wave heights are proportional to the square root of the fetch (distance over water that wind blows) [9].
Deep Water Waves
In deep water, the wavelength (λ) of surface waves is less then the depth (d) of the water (λ < d). They travel at speeds proportional to √λ:
Vertical oscillation is attenuated with depth. The decrease in vertical motion corresponds to halving the cycloid diameter every depth increase of λ/9. The amplitude or height of the surface waves is not directly proportional to wavelength (the common average of h:λ is ~1:20 [9]).
Shallow Water Waves
For wavelength more then 2 times the water depth, the waves are considered to be shallow water waves. In such cases the vertical circular motion of a water particle of that wave becomes elliptical and extends all the way to the bottom of the water column and forms a to-and-fro sloshing motion. Their velocity decreases as the square root of depth decreases ( ). There is also a coinciding reduction in wavelength. The wave height first decreases slightly, then increases dramatically to the point where it becomes unstable and a breaker results [9].