0.1797 ppm wet weight-whole organism to 0.8156 ppm; those at mile 120 

 increased from 0.1797 to 0.5408 ppm (Sparks and Walter, unpublished 

 data) . 

 Sediment 



The past detrimental impacts of sediment on aquatic vegetation, 

 fish habitat, fish food organisms, and the fishes of the Illinois River 

 were described in a previous section. At the present time, sediment 

 continues to enter the river and to fill bottomland lakes and backwaters 

 with each influx of sediment-laden water from the river. 



Sediment affects many uses of the river, in addition to fishing. 

 Many residents of Quiver and Baldwin beaches near Havana bought lake- 

 front property because they enjoy water-based recreation. During the 

 prime months for water recreation, the summer months, the water levels 

 are low and Quiver Lake is now so filled with sediment that it is im- 

 possible to launch a boat in the upper two- thirds of the lake. The an- 

 nual speedboat races at De Pue Lake (mile 211-213) were cancelled in 

 1974 because the water had become too shallow. Mr. Bruce Hillemeyer, 

 co-owner of the Tall Timbers Marina at Havana (mile 120.5), reported in 

 1974 that it cost approximately $50,000 to dredge the channel to the 

 marina every 2 to 3 years, and that this increasing expense, added to 

 other expenses, was forcing him to sell his business. The navigation 

 channel in the vicinity of Kingston Mines (mile 146) was closed to 

 two-way barge traffic for several weeks in 1974 because extensive 

 dredging operations were necessary. 



Once the sediment is in the river and lakes, it can be resuspended 

 by boat traffic or waves produced by wind. The increased barge traffic 

 (Starrett, 1972) associated with the improved navigation channel in- 

 creases the turbidity of the river. The turbulence produced in mid- 

 channel, as well as the washing action along shore, resuspends sediment 

 and thereby increases the turbidity. Starrett (1971) made numerous ob- 

 servations of the effect of barges on turbidity of the river: 



"A towboat underway causes a strong current and 

 washing action on the silt bottom ("false bottom") 

 in shore, which resuspends the silt particles, there- 



62 



