|Lerch, Robert - Bob|
Submitted to: National Cave and Karst Management Symposium
Publication Type: Proceedings
Publication Acceptance Date: 4/30/2002
Publication Date: 7/31/2003
Citation: LERCH, R.N., ERICKSON, J.M., WICKS, C.M. INTENSIVE WATER QUALITY MONITORING IN TWO KARST WATERSHEDS OF BOONE COUNTY, MISSOURI. PROCEEDINGS 15TH NATIONAL CAVE AND KARST MANAGEMENT SYMPOSIUM. 2003. USDA-FOREST SERVICE. TUSCON, AZ. P. 157-168. Interpretive Summary:
Technical Abstract: Karst watersheds with significant losing streams represent a particularly vulnerable setting for ground water contamination because of the direct connection to surface water. Management challenges in this type of karst setting are similar to surface watersheds with regard to implementation of best management practices and responsible urban development. Because of the existing agricultural land-use and future threat of heavy urbanization, two losing stream karst basins were chosen for intensive monitoring in Boone County, MO: Hunters Cave and Devils Icebox Cave. Land use within both watersheds is similar with nearly equal percentages of row-crops, grasslands, and forest. Year-round monitoring was initiated in April, 1999 with the objective of characterizing the water quality status of the main cave streams relative to herbicide, nutrient, and coliform bacterial contamination. Water sampling for contaminants entails grab samples at regular intervals, and runoff event sampling using automated sampling equipment. In the first year, at least one herbicide or metabolite was detected in 94.5% of Hunters Cave samples and 99.6% of Devils Icebox samples. Total nitrogen and phosphorus concentrations were consistently higher in Devils Icebox watershed, and concentrations of either nutrient correlated to stream discharge and suspended sediment levels. Compared to an earlier study at Devils Icebox, total N levels have decreased about 34%, but total P levels have increased 200% over the last 17-19 years. Fecal coliform bacteria levels were generally above the whole body contact standard (200 cfu 100 mL**-1) in Devils Icebox, regardless of flow conditions. Under runoff conditions, fecal coliform levels in both caves can exceed 10,000 cfu 100 mL**-1. Prevailing land management has significantly degraded the water quality in both watersheds.