Hydraulic, geotechnical, geomorphic, and biologic data for the Cache River/Heron Pond area in southern Illinois

Abstract

Heron Pond, located in extreme southern Illinois, lies immediately adjacent to the upper Cache River. The upper Cache River is encroaching on Heron Pond, which has raised the issue of the possibility of a failure of the Heron Pond wall, the area between Heron Pond and the upper Cache River. Hydraulic, geotechnical, geomorphic, and biologic data were collected by the U.S. Geological Survey (USGS) in cooperation with the Illinois Department of Natural Resources, Office of Water Resources (IDNR/OWR) for use in designing a mitigation plan by the IDNR/OWR to prevent the failure of the Heron Pond wall. The river is sluggish during floods with velocities generally 1-2 feet per second. Biologic activity in the area have increased bank instability, which already is a problem because of saturated soils in the Heron Pond wall. In the area adjacent to the Heron Pond, the right descending bank of the upper Cache River receded 0.5 foot between September 21, 1995 and June 25, 1996. Comparisons between two surveys, 1958 and 1995, indicate that the channel near the discontinued USGS streamflow-gaging station near the Burlington Northern Railroad crossing has widened by more than 10 feet with less than 0.5 foot of incision.