THE EFFECTS OF LAND USE ON WATER QUALITY AND AGRICHEMICAL LOADING IN THE FOGELPOLE CAVE GROUNDWATER BASIN, SOUTHWESTERN ILLINOIS

Samuel V. Panno, Walton R. Kelly, C. Pius Weibel, Ivan G. Krapac, and Steven L. Sargent 

Illinois State Geological Survey and Illinois State Water Survey

Abstract

The boundaries of the Fogelpole Cave groundwater basin were estimated and a monitoring station was set up just downstream of two springs that drain the basin. Land use in the groundwater basin is primarily row crop agriculture. Water quality analyses and discharge measurements from the monitoring station have yielded preliminary estimates of mass loading of agrichemicals in water discharging from the basin. Approximately 38,550 kg/yr (85,000 lbs/yr) of NO₃^--N and 19 kg/yr (42 lbs/yr) of atrazine were discharged from the approximately 31.8 km² (12.3 mi²) basin. This represents about a 20% loss of applied N and about a 1.5% loss of applied atrazine. In addition, bacteria in the spring waters include up to 16 species present in millions of colonies per 100 mL water. These bacteria were dominated by Klebsiella pneumoniae, Escherichia coli, and Pseudomonas spp., the first two of which are fecal coliforms. The prevalence and dominance of Escherichia coli over fecal streptococci suggests that private septic systems, rather than livestock, are the principal source of fecal bacteria responsible for degrading water quality in the study area.