By Brad Walker, Rivers Director July 11, 2014
Illustrations and other contributions by Joe Mohr
1. Introduction – What we have wrought on our Midwestern rivers
Row crop agriculture has always been intricately tied to the promotion of barge navigation on our large Midwestern rivers, primarily for exporting corn, wheat and more recently soybeans. Agricultural interests were heavy promoters pushing to change our rivers into barge canals and to this day continue to lobby for expansions of the system.
Because none of our rivers are deep enough for their full lengths for the minimum nine-foot drafts required for towboats used, especially during low flow periods, engineers called for alterations on an unprecedented scale to create an adequate channel depth and width for these over-sized barges. Conveniently, the river alterations actually reinforced the connection with agriculture by easing the conversion of floodplains to cropland, in some locations creating new land that was immediately placed into agriculture.
On the Missouri River this involved constructing massive dams upstream and then shortening, straightening and narrowing the lower portion of the river to the point that it has little resemblance to the original river. About 522,000 acres of floodplain and riverine habitat were lost through the process of constructing a nine-foot channel; all of that acreage altered and much of it, as well as land along the river created by the process, became levee-protected corn and soybean fields.
Congress authorized the US Army Corps of Engineers (Corps) to channelize the river several times. The final iteration of this process is called the Bank Stabilization and Navigation Project began inthe early 1950s and was completed about 1981, paid for by taxpayer funding. Massive impacts to river habitats have resulted.
Much the same has occurred in the Upper Mississippi River (UMR) and Illinois River from the construction of the nine-foot channel there. In the areas north of St. Louis where the rivers are not consistently deep enough they were impounded with locks, which are low-head type dams constructed solely for navigation purposes creating pools rather than flowing rivers (See Figure 2).
The alterations constructed below St. Louis in the Mississippi River were much the same as Those built within the Missouri River. Again, the floodplains were the site of large losses of natural habitat, and remaining floodplains were turned into flattened monoculture-row crop landscapes protected from the river by levees.… Read the rest