EFFECTS OF DECREASING WATER DEPTHS ON THE SEDIMENTATION RATE OF ILLINOIS RIVER BOTTOMLAND LAKES¹

Abstract

The annual sedimentation rate of lakes and reservoirs is usually not evaluated for changes in depth relative to time. By using a linear regression with depth as the independent variable and annual rate of fill as the dependent variable the effect of changing depths is negated. According to both profile and linear regression analyses, Peoria Lake is filling faster in the more recent of two time spans but Lake Meredosia's increasing sedimentation rate is shown only by a linear regression. The probable cause for increasing sediment loads in the Illinois River is an almost twofold increase in row crop production in Illinois.

SEDIMENTATION IN LAKE ONALASKA, NAVIGATION POOL 7, UPPER MISSISSIPPI RIVER, SINCE IMPOUNDMENT1

“…Given the sedimentation that has occurred elsewhere along the Upper Mississippi (GREAT I, 1980b) and other rivers in the upper-midwest (Steffeck, et al, 1980), it is remarkable that there has been relatively little loss of reservoir capacity in Lake Onalaska since 1937. The sedimentation rate for Lake Onalaska has not been as great as previously reported, based upon our analyses of data from pre-and post-impoundment surveys.…”

Long‐term effects of navigation dams on a segment of the upper Mississippi River

“…Reservoir volume reduction and the filling-in of backwater and side-channel habitats through sedimentation has been reported for all 27 pools of the river main-stem (McHenry et al, 1976;McHenry et al, 1984;Nielsen et al, 1984;Chen and Simons, 1986;Eckblad, 1986;Keown et al, 1986;Korschgen et al, 1987). Even more substantial losses of river volume have been reported for the Illinois River portion of the basin (Steffeck et al , 1980;Bellrose et al, 1983;Sparks, 1984).…”