When the upper Cache River emerges from the Shawnee Hills it intersects a wide, relatively flat valley stretching from the Ohio River on the east to the Mississippi River on the west. The Cache intersects the Ohio River not far upstream from its junction with the Mississippi River. When early French explorers first encountered the mouth of the Cache it was jammed with logs and obscured from view. Thus, it was the named Cache, meaning hidden or stored in French.
The Cache Valley, which is actually the ancient course of the Ohio River, receives water flowing into it from the Cache River and several other tributaries. During major flood events backwater from the Ohio at the mouth of the Cache River would actually flow eastward, or backward along its ancient course, 80 miles to rejoin the Ohio at the mouth of Bay Creek.
The 11,000-acre area between Bay Creek at the Ohio River and the Cache River, referred to as the Black Sough, was described in 1807 by Public Land Surveyors as a “lake,” as a “pond,” as “inaccessible” and as having “water too deep to wade.” Section lines had to be surveyed on ice or not at all. The Cache valley downstream from the Black Slough was also described by terms such as swamp, lakes, ponds, and scatters.
This unique landmass at the junction of two of the word’s greatest rivers, with its mystifying, complex and crazy hydrology, was basically considered to be “inaccessible and drowned.” The only logical solution for accessing the valuable timber and conversion to farmland was to drain the massive wetlands.
By the 1870s sawmills began processing the plentiful timber for lumber, railroad ties, boxes and charcoal. Drainage and land-clearing efforts were beginning to bring bottomland under cultivation. But, the worst was yet to come. In 1905, A.H. Bell, Chief Engineer of the Cache River Drainage Commission explained that drainage of the “exceedingly crooked and winding…meanders” of the Cache could be increased significantly by digging a ditch straight into the Ohio.
The Post Creek cutoff was a great success at draining the land—but its effect on the ecology and hydrology of the watershed…not so much! (To be continued.)
[Historical reference credit: Cache River Area Assessment: Early Accounts of the Ecology of the Cache River Area, John White, Illinois Department of Natural Resources, 1997]