A seiche is a standing wave oscillating in a body of water, like the water that sloshes back and forth in a bathtub or cup of water when disturbed. They typically occur in enclosed waterbodies such as lakes, reservoirs, or even swimming pools. These waves can be surface waves or internal waves.
What causes a seiche?
They are typically caused by strong winds and rapid changes in atmospheric pressure that push water from one end of a water body to the other. After the wind event, the water rebounds to the other side of the enclosed area and continues to oscillate back and forth for hours or even days, depending on the size of the lake.
Seiches may be noticed under ordinary water conditions as a result of periodic changes in water level or underwater currents associated with the oscillating movement. At some locations and times, these sea-level oscillations and currents may produce hazardous or even destructive conditions. Internal waves form that can be up to 10 to 30 meters high, all unseen from the lake surface.
Seiche waves generate currents and turbulence that rhythmically flow back and forth. These currents can cause bottom water to come to the surface, and can also mobilize lake sediments and carry them into the water.
To learn more about seiches, watch the video from Larratt Aquatic Consulting Ltd.
National Ocean Service, NOAA, What is a seiche? 3 March 2021 https://oceanservice.noaa.gov/facts/seiche.html
Stevens, C. L., & Lawrence, G. A. (1997). Estimation of wind-forced internal seiche amplitudes in lakes and reservoirs, with data from British Columbia, Canada. Aquatic Sciences, 59(2), 115-134. https://bit.ly/3dbjUV1
Author: Marie McCallum