Kingsley Dam & Lake McConaughy
The construction of the Kingsley Dam was one of the largest public works projects in Nebraska during the 1930s. Construction began in 1936 and was completed five years later at a cost of more than $43.5 million. Kingsley is one of the largest earthen dams in the world.
Building was an engineering marvel. Most of the soil surrounding the dam is very sandy. Workers had to drive a solid wall of interlocked sheet steel pilings across the riverbed and down between 30 and 160 feet. The pilings passed through the sand and gravel until they reached an impervious layer of Brule clay. Then over those steal pilings workers pumped loess soil – a fine grained clay and silt soil found more often in Iowa than Nebraska – to a finished height of 162 feet. That’s the height of a 10-story building. The water then was drained out of the loess and the soil hardened into a solid core. Over the core, local sand and gravel was pumped from a pit. The entire dam contains 25 million cubic yards of earth and other material.
A U.S. highway runs across the top of the dam for 3.5 miles. As Lake McConaughy behind the dam filled up, it created over 100 miles of shoreline and beaches that have been compared to Hawaii. At full storage of 1,948,000 acre-feet of water, “Big Mac” is 22 miles long, four miles wide, and 142 feet deep near the dam. When full, the lake covers 35,700 acres.
Besides the irrigation and electrical power that the dam creates, it has also produced a recreational boom for boating and fishing. The lake also attracts a large number of windsurfers. And in an unexpected development, bald eagles have discovered that the water coming out of the Sutherland power generating plant stays warm all winter. The eagles feast on fish when other bodies of water are frozen. One winter day, 386 bald eagles were counted in the area.
Written by Bill Ganzel of the Ganzel Group. First written and published in 2003.