During the centuries that followed the lakes origin, climate shifts caused water levels to fluctuate between 6 and 12 meters every few hundred years. Sediment analyses by geologist Edward Callender, published in his 1968 University of North Dakota doctoral thesis, indicated that the lake might have been completely dry 6,500 years ago. After the lake last rose to its maximum elevation and began overflowing, water levels continued to fluctuate in response to alternating dry and wet periods. A persistently dry climate 500 to 600 years ago held levels at relatively low elevations for perhaps as long as 200 years. Wetter conditions followed, raising the lake to levels that prevailed until the late 1800s. Levels then began dropping precipitously, falling to the lowest-recorded elevation by 1940 before rising again.
Whether Lake Minnewaukan was completely dry at times or not, periodic drawdowns during dry conditions reduced its immense volume to numerous remnant lakes scattered across the south-central region of the basin. Nonindigenous people who settled the region beginning in the mid-1800s named the largest and most prominent of these remnants Devils Lake, perhaps because of the lakes highly saline, undrinkable water, or perhaps in tribute to Sioux warriors whose canoes were often capsized in the lakes treacherous, storm-tossed waters.
In 1964, Devils Lake consisted of three principal basins called West Bay, Main Bay and East Bay. West Bay then was essentially dry and Main Bay covered about 53 square kilometers. The Rock Island State Military Reservation separated East Baywhich covered about 27 square kilometersfrom Main Bay. According to T. E. B. Pope of the U.S. Bureau of Fisheries, Main Bay and East Bay had become isolated during the 1890s after lake levels dropped about 6 meters during the previous 25 to 30 years. Besides Devils Lake, other major lakes nearby included Pelican Lake to the west and, to the east, East Devils Lake, Swan Lake, West Stump Lake and East Stump Lake, in that order.
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