Phase 2: Springs of Illinois – Project Summary

The Aquatic Biodiversity, Hydrogeology, and Water Quality of Seven Springs in the Shawnee Hills of Southern Illinois – Project Summary

D.W. Webb, M.J. Wetzel, and L.R. Phillippe M.J. Wetzel, and L.R. Phillippe
Illinois Natural History Survey (INHS) 

1816 S. Oak Street, Champaign, IL 61820

P.C. Reed and T.C. Young
Illinois State Geological Survey
615 East Peabody Drive, Champaign, IL 61820

This webpage presents a summary of the second phase of a long-term project focusing on the biodiversity, hydrogeology, and water quality of springs in Illinois.


The biodiversity, hydrogeology, and water quality of 10 karst springs in the sinkhole plain of the Salem Plateau Section, Monroe and St. Clair counties, Illinois, were studied from November 1994 through August 1995. Of concern were the potential effects of nitrate nitrogen and the herbicides Atrazine, Alachlor, Cyanazine, and Metolachlor on the biological communities in these springs.

Aerial views of numerous sinkholes and sinkhole ponds in the karst region of southwestern Illinois.  Photos © Joel Dexter, ISGS photographer.

During this study, 141 aquatic macroinvertebrate taxa were identified from these springs. Taxa richness ranged from 18 to 82 and averaged 42 taxa per spring. Aquatic oligochaetes, amphipods, isopods, and turbellarians were the most abundant organisms. Aquatic insects (80 taxa) composed the most diverse group of macroinvertebrates, but generally were low in abundance. Oligochaete worms (33 taxa) represented the most diverse and often most abundant group of non-insectan aquatic macroinvertebrates occurring in these springs. Of particular interest was the collection of Varichaetadrilus angustipenis (Tubificidae), andAllonais inaequalis (initially identified as A. paraguayensis) and Bratislavia unidentata (Naidinae) – three oligochaetes each considered rare in Illinois and throughout their North American distribution.

Two cave stream amphipods, Crangonyx forbesi and Gammarus troglophilus, were collected from seven and eight karst springs, respectively. Two cave inhabiting isopods, Caecidotea intermedia and C. packardi, were collected from one and three of these springs, respectively.

A positive linear correlation between drainage basin area and aquatic macroinvertebrate taxa richness was determined for nine of the 10 springs studied.

No animals or plants listed as endangered or threatened by the federal government or the State of Illinois were collected from or observed in the vicinity of these 10 karst springs.

No aquatic macrophytes were present at any of the 10 karst springs during our surveys.

Geochronologically, the 10 karst springs were assigned to three formations of the Valmeyeran Series of Mississippian age. Age dating of precipitated limestone earth materials indicated that springs in Monroe and St. Clair counties were actively discharging 10,840 (± 170) years BP.

Measured discharge from springs and their associated springbrooks ranged from 0 to 590 L/sec. Springbrook gradients ranged from 0.07 to 25.6 m/100 m.

The 83-year record monthly rainfall in 1995 provided insight into the ubiquitous nature of herbicides in the groundwater system associated with 10 karst springs; six distinctive patterns of herbicide occurrence were recognized. Positive linear correlations between chloride concentration and discharge, specific conductance and alkalinity, dissolved calcium, hardness, and total dissolved solids were determined.

Nitrate nitrogen was detected in all 40 water samples. Concentrations of nitrate nitrogen ranged from 0.26 to 7.64 mg/L (mean 3.83 mg/L). None of the 40 water samples contained concentrations of nitrate nitrogen that exceeded the U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Level (MCL) of 10 mg/L.

Alachlor was detected in 11 of the 40 water samples (27.5%). Concentrations of Alachlor ranged from

Atrazine was detected in 29 of the 40 water samples (73%). Concentrations of Atrazine ranged from

Cyanazine was detected in 9 of the 40 water samples (22.5%). Concentrations of Cyanazine ranged from

Metolachlor was detected in 19 of the 40 water samples (47.5%). Concentrations of Metolachlor ranged from

Citations for publications summarizing this research

1. project report to the funding agency supporting this research:
Webb, D. W., M. J. Wetzel, P. C. Reed, L. R. Phillippe, T. C. Young. 1996. Karst springs in the sinkhole plain of Illinois: Their community diversity and hydrogeology. Illinois Natural History Survey Center for Biodiversity Technical Report 1996(11). 122 pp. Prepared for the Illinois Groundwater Consortium Research Development and Administration, Southern Illinois University at Carbondale, 62901-4709.

2. Proceedings of a symposium sponsored by the funding agency:
Webb, D.W., M.J. Wetzel, P.C. Reed, L.R. Phillippe, and T.C. Young. 1996. Biodiversity, hydrogeology, and water quality of 10 karst springs in the Salem Plateau Section of Illinois. Pp. 146-185. In M. Davis, Editor. Research on agricultural chemicals in Illinois groundwater: Status and future directions VI. Illinois Groundwater Consortium, Office of Research Development and Administration, Southern Illinois University, Carbondale.

3. Peer-reviewed publication on springs:
Webb, D.W., M.J. Wetzel, P.C. Reed, L.R. Phillippe, and T.C. Young. 1998. The macroinvertebrate biodiversity, water quality, and hydrogeology of ten karst springs in the Salem Plateau Section of Illinois, USA. Pp. 39-48. In L. Botosaneanu (ed.). Studies in Crenobiology – The biology of springs and springbrooks. Backhuys Publishers, Leiden, The Netherlands. 261 pp. ISBN 90-73348-04-8.

Questions, Comments, Suggestions, or Ideas?

Please e-mail them to me at: mjwetzel{AT}

Copyright © 1990 – 2023, by Mark J. Wetzel (Illinois Natural History Survey Division of Biodiversity and Ecological Entomology, Champaign) unless otherwise noted; All Rights Reserved. This website contains original, copyrighted material; it is being provided here as a professional courtesy, exclusively for your private, non-commercial use. Reference to or redistribution of any part of the information contained herein – whether it be through oral, printed, electronic, or other tangible medium of expression – shall acknowledge the Illinois Natural History Survey (INHS), the Illinois State Geological Survey (ISGS), and this website as its source. Should you have any questions whatsoever regarding the warranty, liability, or proprietary rights of, or credits for information contained within this website, please refer to the INHS License Agreement. [To the best of my knowledge – and with the exception of the INHS logo – all icons, line breaks, dots, arrows, and globes are not copyrighted.]

Suggested citation for this electronic web site:

Webb, D.W., M.J. Wetzel, P.C. Reed, L.R. Phillippe, and T.C. Young. 2023. Biodiversity, hydrogeology, and water quality of 10 karst springs in the Salem Plateau Section of southwestern Illinois – Project Summary. World Wide Web URL:
[ ]. 07 April 2023.

Please also visit our institutional websites:
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and the
Illinois State Geological Survey