Hydrodynamic Modeling of the Peoria Lake: Largest Bottomland Lake on the Illinois River

Peoria Lake, located at River Mile 157-179 on the Illinois River, is the largest bottomland lake on the Illinois River. This lake extends for about 35 km within the Peoria pool of the Illinois River. Geologically, the lake was formed by the constriction exerted by tributary deltas which flooded the broad, wide, and shallow floodplains. In 1939, Peoria lock and dam was constructed to aid in the commercial navigation especially during low flow periods. Over the years, Peoria Lake lost more than 80 percent of its original capacity due to sediment deposition. Research conducted has shown that as much as 50 percent of the sediment could be contributed by the local bluff tributaries draining about 4 percent of the total drainage area of the lake. One of the most promising alternatives for the revitalization of Peoria Lake is to remove the deposited sediments by dredging and utilizing the same sediments to build artificial islands within the lake. In order to test the viability of such an alternative, two-dimensional unsteady SMS has been calibrated and verified for the entire 35 km reach of the river. Alternatives such as artificial islands of various shapes and sizes with associated deep water channels are being tested to determine the feasibility of constructing such artificial islands with dredged materials and maintaining the dredged channel(s) as deep water habitats. It is suspected that one or two islands with dredged materials may be built in the near future within the channel border area of Peoria Lake. This paper presents some of the results of the hydrodynamic modeling work for this specific project.