USING GEOLOGIC MAPS, EXISTING GROUNDWATER QUALITY DATA, AND GEOSTATISTICS TO PREDICT GROUNDWATER QUALITY IN THE CRYSTALLINE ROCK TERRANES OF NORTH CAROLINA

Many attempts have been made in the past to try to correlate basic groundwater chemistry with rock type in the North Carolina piedmont and mountain regions. However, this “Holy Grail” of groundwater quality mapping has so far remained elusive due to the lack of sufficient groundwater quality data and the lack of detailed geologic mapping in many regions. The recent North Carolina legislative mandate that all new private water supply wells be tested for inorganic parameters, in addition to detailed geochemical profiling performed at hydrogeologic research station sites throughout the N.C. piedmont and mountains as part of the Division of Water Quality’s Resource Evaluation Program has resulted in a significant increase in the amount of available groundwater quality data. In addition, recent detailed geologic mapping in the piedmont and mountains performed by the N.C. Geological Survey has resulted in an improved understanding of bedrock geology in areas where this mapping has been completed.

Along with the substantial new groundwater quality database and high resolution geologic mapping, new geostatistical methods are being developed that are capable of helping to predict the concentrations of anthropogenic and naturally occurring groundwater contaminants in areas where existing groundwater quality data is sparse. An overview of these recent developments is presented, along with a preview of the ways that these developments may be used to advance our understanding of the science and provide benefit to our citizens.