Poorly Drained Soils and Geomorphology of Glacial Lake Douglas in Illinois

Soil characteristics and geomorphology were investigated in an area designated Glacial Lake Douglas, in Douglas County in east-central Illinois. The study area was once covered by a glacial lake, with a surface elevation of approximately 650 feet, which occupied a broad, shallow depression in the Wisconsinan till plain. Beneath the solum there were clayey, silty, and sandy sediments which had been deposited in a lacustrine environment, and glacial till. X-ray analyses indicated that the solum was mainly of loessial origin, while the lacustrine sediments were outwash materials from the glaciers which deposited the nearby Wisconsinan till. The lakebed sediments were thickest southwest of the Embarras River and became thinner northeast toward Newman. Laminated, clayey sediment was absent in a wide area west-southwest of Camargo, probably because this was a delta when glacial meltwaters filled the lake. Elevation of the top of the clayey sediment was lowest close to the main drainage outlet, and it became hig...