Little Wabash Project
Diane Burns, Ph.D. and Dave Viertel, Ph.D.
Geologically-speaking, rivers are extremely dynamic, cutting back and forth and re-inscribing their channel paths into the underlying and laterally adjacent sediments numerous times over the years. Rivers are continuous eroders of bedrock as well as bank material, constantly reshaping the landscapes through which they course. Through time, a river’s channel can move a fair distance laterally – a change of 750 meters’ distance is not uncommon. While these lateral changes in a protected wilderness area may be interesting, course changes in an area with distinct ownership rights become a critical issue to landholders.
The Little Wabash River in east-central to southern Illinois is a meandering river that has its headwaters in southwestern Coles County and which flows southward approximately 200 miles to its confluence with the Wabash River. The river cuts through unconsolidated glacial deposits of the Illinoian Glasford and Wisconsinan Wedron Formations, which are draped over underlying bedrock. The river changes in elevation a little over 350 feet between its highest and lowest points, which are approximately 110 miles apart (Limno-Tech, Inc. 2006), a gradient of 3.2 ft/mi. The watershed in which the Little Wabash River flows is primarily devoted to agricultural uses, yielding crops such as soybean, corn, winter wheat and hay (IL Department of Agriculture, 2000). The river wends its way across distinct land holdings, many of which are not owned by the same entity on both sides of the river. Any change in the stream’s pathway means a loss or gain of acreage directly impacting landowners adjacent to the channel.
The historical channel of the Little Wabash River will be delineated using archival aerial photography dating back to the 1930’s. Sources include the Illinois Geospatial Data Clearinghouse, USDA aerial surveys, and hardcopy imagery archived at the county level. The historical path of the river will be compared to the current channel as determined by high resolution multispectral satellite imagery and field surveys. Results will be presented as an animated geospatial dataset, demonstrating the dynamic nature of the river system.