Reference conditions for streams in the Grand Prairie Natural Division of Illinois

As part of the Critical Trends Assessment Program (CTAP) of the Illinois Department of Natural Resources, 18 potential reference quality stream reaches in the Grand Prairie Natural Division were evaluated in May 2004 and 2005. This agriculturally dominated region, located in east central Illinois, is among the most highly modified in the state. Illinois Environmental Protection Agency high quality fish stations, Illinois Natural History Survey insect collection data, and best professional knowledge were used to choose which streams to evaluate. The quality of these sites was assessed using the species richness of Ephemeroptera, Plecoptera, and Trichoptera insect orders (EPT), a modified Hilsenhoff Biotic Index (HBI), and a 12 parameter Habitat Quality Index (HQI). Reference quality streams were compared to 21 randomly selected meandering and 30 randomly selected channelized streams which were assessed by the Critical Trends Assessment Program between 1997 and 2001. The results from this research indicate that reference streams were consistently of higher quality than random streams, and are representative of the biotic potential of the Grand Prairie. A GLM ANOVA showed that both channel alteration and stream size were significant factors governing stream quality. Streams with meandering courses and a larger wetted width were generally healthier in terms of EPT, HBI, and HQI. However, HBI appeared to be a less sensitive measure of stream quality. The extent of stream channelization, especially in terms of loss of pool variability and sinuosity, appeared to be a major cause of degradation in stream quality. A regionally specific rating scale now exists for the Grand Prairie that puts 51 randomly sampled streams into context. The findings of this research are consistent with earlier findings for statewide random sites reported by CTAP. Overall, 31.4% of randomly chosen streams in the region were classified as having fair stream quality, 47.1% were of poor condition, 13.7% were good quality, and 7.8% were excellent quality (Fig. 27). This study has provided additional evidence that stream quality in Illinois is low and is a result of extensive channel alteration.

Name thesis:degree_name

M.S. (master's)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environmental Science

Grantor dc:publisher

University of Illinois

Year dc:date

2017

Author dc:creator

• Sangunett, Brandi

Contributors dc:contributor

• DeWalt, R. Edward
• Herricks, Ed
• McIsaac, Gregory

• Illinois
• Critical trends
• streams
• Grand Prairie Natural Division
• EPT Taxa
• Reference Streams

Statement dc:rights

• © 2005 by Brandi Sangunett. All rights reserved.

Language dc:language

en

Identifier

Sangunett, B. M. 2005. Reference conditions for streams in the Grand Prairie Natural Division of Illinois. M. S. Thesis, University of Illinois at Urbana-Champaign, Urbana, Illinois.

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/96666