West Lake Okoboji Area Insights

Referred to locally as the lake turning over the thermocline is a feature of lakes with deep water. The water on the top of the lake changes temperature much more variably during the year. On West Lake, it can reach as much as 75 degrees in July while the water below, greater than 35 or 40 feet deep is relatively stable around 45 degrees. In the fall and early winter, the top strata of the lake will cool to below 45 degrees, and then because it becomes denser, it will "sink" below the lower strata, thus, displacing it and making the lake "turn-over". In the deepest part of West Lake (near the 136ft mark), no light is availble, and hence little life is known whether fish or plant. Typically questions are raised as to why the surface water gets dirty for a short period of time in the fall, this this is the standard answer.