Effect of Sedimentation on Floods in the Kickapoo Valley, Wisconsin

Abstract

Listen

Translate article

The Kickapoo River, a tributary of the Wisconsin River, is the largest stream entirely within the rugged Driftless Area of the Upper Mississippi Valley. The drainage area is submaturely dissected, with an average relief of about 400 feet. Deforestation, cultivation, and grazing of the sloping ridge crests and valley sides have resulted in greatly accelerated soil erosion, and consequently fluvial sedimentation has also been accelerated. Nearly all the dark-gray or black first-bottom soils have been covered by stratified brownish modern sandy silt since about 1850. Numerous test borings indicate that the flood plains of the main Kickapoo River and the lower parts of two main tributaries have been aggraded an average of about 2.5 feet. Re-surveys of river cross sections beneath railroad bridges indicate an average rate of river-channel aggradation of about 1 foot in twenty years, and it is concluded that the river and flood plain are being aggraded at about the same rate. Excessive sedimentation from floo...