Possible Biological Impacts of Wave Wash Resuspension of Sediments Caused by Boat Traffic in the Illinois River.

摘要

The physical effects, such as waves and turbulence, associated with the passage of a boat are more pronounced in a narrow, shallow river channel such as the Illinois Waterway, than in the relatively wider and deeper Mississippi River. The bed material in the Illinois below Hennepin (river mile 207) is composed predominantly of silts and clays, which are more easily resuspended by boat traffic and which also take longer to settle, than the sands which largely comprise the bed of the Mississippi. The Illinois thus seems to be especially vulnerable to the physical effects of increased boat traffic. In addition, the areas that are most productive fish and wildlife in the Illinois Valley, the side channels, backwaters, and bottomland lakes, which flank the main channel, are especially vulnerable to siltation, because the current is reduced in these areas and suspended material tends to settle out. The purpose of this report is to evaluate the impact of increased frequency of wave wash and resuspension of sediments, resulting from increased boat traffic, on the biota in the channel and lateral areas of the Illinois River. (Author)