Figure - Environmental Benefits

Environmental Benefits


The nesting habitats of the Least Tern, an endangered species of bird, have been preserved. By building Bendway Weirs, no dikes across the sandbar have been needed. Thus the habitats have gone undisturbed and remain isolated from the main shore making it harder for predators and all-terrain vehicles to invade the habitat. The population of the Least Tern has remained constant along Dogtooth Bend since construction was completed.

The wider, shallower channels, where currents move more slowly, provide an enhanced aquatic environment for many species of fish. In addition, submerged Bendway Weirs act as an underwater reef and create sites for aquatic invertebrate.

Figure - shallower channels

The Missouri Department of Conservation tested the diversity in habitats surrounding a test section of notched dikes. Their raw data showed a total of 4,512 fish and 45 different species. After studying the data, they found an increase in diversity and numbers of micro-invertebrates. To a lesser degree, fish communities were also found to have greater diversity. In addition, the larger problem of aquatic environment becoming terrestrial was resolved. The river channel is maintained, structures are basically self-maintained and biological diversity has increased.

Tests by the Illinois Department of Conservation studying habitat diversity surrounding bankline and off bankline revetments showed the use of larger rock provided habitat for a greater number of fish than either small stone revetment or the natural river bank.

Isolated sandbars created by the various navigational structures provide nesting sites for the endangered Least Tern. These sandbars are away from man’s encroachment which helps aid their development. In addition, the easy access from slow water to fast water provides valuable spawning ground for the endangered Pallid Sturgeon.

Each structure is a piece of a giant jigsaw puzzle, having to “fit” exactly to create a safe and dependable navigation channel and at the same time, stimulate the river’s biological diversity. Innovative concepts will continue to be designed and evaluated as the river engineers proceed with the environmental river engineering project: to work in harmony with the natural laws of the river.