Cache River, Southern Illinois

The Challenge

The Cache River Basin in southern Illinois is a unique ecosystem holding important wetlands, including one of only sixteen in the United States listed by the United Nations’ UNESCO division as wetlands of “international importance.” Before logging and conversion to agriculture, over 240,000 acres (97,124 ha) of the Cache River’s watershed were covered with cypress-tupelo (Taxodium distichum, Nyssa aquatica L.) swamps. Today, the area holds two of the largest cypress trees in the United States and some of the oldest living cypress trees known. The Cache River Watershed in southern Illinois has a complex natural history influenced by glaciation, perhaps tectonic events in the past 1,000 years, and certainly by radical alteration after European settlement.

In 2005, LRRD was hired by the Cache River Joint Venture Partnership to investigate the evidence for water levels in the middle Cache River Valley prior to extensive drainage network alteration beginning in the late 1800s. Our research included analysis of historical records and geomorphology of the Cache Valley, and may have uncovered evidence that some wetlands in the Valley have origins as “sunklands” formed by tectonic events in the past 1,200 years.

Download our full report here. Special information regarding this research here.


The Cache River Joint Venture Partnership, The Nature Conservancy, the Illinois Department of Natural Resources and the US Fish and Wildlife Service, with the Natural Resources Conservation Service, Illinois State Geological Survey, and siesmologist Martitia Tuttle of M. Tuttle and Associates.

Plat map drawn from the 1807 Public Land Survey of the Cache River

A plat map, date unknown, drawn from the 1807 Public Land Survey of the Cache River. These plats were invaluable in determining the extent of flooded land when the survey was done. From the Illinois State Archives.


Excerpt from the USGS Dongola 15' quadrangle showing early channelization of the lower Cache

Excerpt from the USGS Dongola 15' quadrangle, published in 1919, showing early channelization of the lower Cache. During the first part of this century the Cache’s valley was extensively altered by logging and drainage projects.


Excerpt from the 1903 Bell Survey, which included a long profile survey of the Cache River

Excerpt from the 1903 “Bell Survey," which included a long profile survey of most of the Cache River. This survey, which included streambed and bank elevations, was analyzed to determine geomorphology of the river before it was altered. Here the red line is the surveyor’s proposed channelization route.