Fox River Watershed Investigation: Stratton Dam to the Illinois River Phase II, Analyses of Biological Data

This report summarizes biological data collected in the Fox River watershed. It describes database development and data sources available for the study area, the Fox River watershed from Stratton Dam to the Illinois River. Biological evaluation using fish and macroinvertebrate indices and habitat data analysis are included in this report. The structure of the existing water and sediment quality database, FoxDB, was expanded to include individual biological samples and information on species abundance. The structure was designed to help calculate various metrics describing fish and macroinvertebrate communities in indexes of biotic integrity. The database was populated with biological and habitat information collected in the study area, including 86 macroinvertebrate samples from 63 monitoring stations and 201 fish samples from 102 stations. The Macroinvertebrate Biotic Index (MBI) and selected metrics of the revised Illinois Index of Biotic Integrity (IBI) were evaluated for changes in flow regime (free-flowing and impounded), stream size (mainstem and tributaries), and spatial location (upper more urbanized part and lower rural part of the study area). Most biological indicators imply the impairment of mainstem sites, especially in impounded portions of the river, and suggest higher impairment in the upper urbanized part of the watershed.