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Mackinaw River Watershed Project, central Illinois

The Challenge

The Mackinaw River Watershed, a 1,100-square-mile basin in central Illinois, holds some of the most diverse aquatic communities in the state. These ecosystems are threatened, however, by intensive row-crop agriculture and other impacts.

Little River Research & Design owner & principal Steve Gough played a key role in conceptualizing conservation efforts and in writing a proposal for EPA 319 funding. Working in cooperation for The Nature Conservancy, he assessed scores of sites in the Mackinaw River Watershed. He developed watershed-based approaches to aquatic ecosystem management and hydraulic geometry relationships for this complex, glaciated landscape. Field assessment included long profile surveys and detailed geomorphological analysis at 28 sites.

The Conservancy, along with state and federal agencies, are now using this work to guide efforts to conserve and reintroduce freshwater mussels to the Mackinaw River Watershed.

Steve’s work on the Mackinaw River was published in two volumes. Copies are available from The Nature Conservancy‘s Peoria, Illinois Field Office.


The Nature Conservancy, USEPA, Illinois Environmental Protection Agency, Illinois Department of Natural Resourcesand Illinois Natural History Survey.

The lower Mackinaw River. This reach runs through sandy material left behind after glacial drainage in the Illinois River basin, and shows a strong tendency for lateral movement and regular meanders.
Steve surveys a reach in the Middle Mackinaw. Over 16 miles of river were surveyed in detail, in both long profile and cross-section.
Steve’s work included extensive analysis of geomorphology and hydraulic geometry throughout the Mackinaw River Watershed. The chart above shows the results for bankfull channel width, along with data from Dunne and Leopold (1978).