What is a Seiche?
Seiches are tide-like rises and drops in lakes caused by prolonged strong winds that push water toward one side of the lake, causing the water level to rise on the downwind side of the lake and to drop on the upwind side. When the wind stops, the water surges back and forth, with the near shore water level rising and falling in decreasingly small amounts on both sides of the lake until it reaches equilibrium. The effect is caused by resonances in a body of water that has been disturbed by one or more of a number of factors, most often meteorological effects (wind and atmospheric pressure variations), seismic activity. Gravity always seeks to restore the horizontal surface of a body of liquid water, as this represents the configuration in which the water is in hydrostatic equilibrium.
The Swiss hydrologist François-Alphonse Forel first promoted the term in 1890, who had observed the effect in Lake Geneva, Switzerland. The word originates in a Swiss French dialect word that means "to sway back and forth", which had long been used in the region to describe oscillations in alpine lakes.
May 9, 2007 12:31 PM | Category: Flood