THE POTENTIAL FOR RECONNECTION ON THE LOWER ILLINOIS RIVER

Author

Ann Rushing, Southern Illinois University CarbondaleFollow

Date of Award

12-1-2015

Degree Name

Master of Science

Department

Geography and Environmental Resources

First Advisor

Remo, Jonathan

Abstract

The purpose of this study is to evaluate leveed floodplains along the La Grange segment (Peoria to La Grange, IL) of the Lower Illinois River (LIR) for their potential in creating both specific and diverse array of floodplain habitats if they were to be hydrologically reconnected. To better understand the potential habitat availability within the levee protect floodplain of the La Grange segment, the Land Capability Potential Index (LCPI) was used. The LCPI uses hydrological, hydrologic, land-surface elevation, and soil data to create an index of potential physical habitat patches which can be applied to assess the suitability of a particular floodplain area for a particular species of interest, such as the threatened Decurrent False Aster, Boltonia decurrens. In addition, we used spatial statistics software (FRAGSTATs) to assess reconnected floodplain areas physical-habitat (LPCI patch) heterogeneity and screened floodplain areas which may provide moist-soil habitats. Most of the B.decurrens habitat occurs (>50%) along the southern portion of the La Grange segment within Clear Lake and Beardstown levee districts. Clear Lake and Beardstown levee districts also contain the largest diversity in physical habitat patches. Moist-soil habitat is mostly located in the northern portion of the LaGrange segment with the majority of this habitat type found within the Spring Levee district (31.7 km2). The levee district with the most potential to enhance important habitat types and physical habitat diversity is the Clear Lake Levee District.