USE OF DISCRIMINANT ANALYSIS FUNCTIONS TO DETERMINE FLOWPATHS IN KARST AQUIFERS IN PORTIONS OF THE INNER BLUEGRASS KARST REGION, KENTUCKY

Groundwater flow in many karst aquifer is thought to concentrate in discrete zones or ‘conduits’ – features such as joints, fractures, or cave passages. When investigating such aquifers, practitioners are often driven to specialized labor- and time- intensive methods, such as dye-tracing studies. Early work in the 1980s in the Inner Bluegrass Karst Region of central Kentucky suggests that geochemical signatures derived from basic water quality parameters commonly included in water quality studies may be sufficient to determine initial flow relationships without the need for dye-tracing. The early work reached over 80% accuracy in classifying groundwater samples into their respective ‘groundwater basin’ determined by dye-tracing.

At a point in time over 20 years later, and with notable land-use change in the Inner Bluegrass Karst Region, follow up samples were collected in a ‘double-blind’ fashion and preliminary results were obtained for this new dataset. These preliminary results from a modern test of this ‘geochemical signature’ statistical approach will be presented along with a detailed explanation of the method. These new results indicate the method holds promise, provided that an adequately sized water quality database exists. Plans for ongoing testing of the method will also be presented.