Karst springs, groundwater and surface runoff in the calcareous Alps: assessing quality and reliance of long-term water supply

The interdisciplinary geohydrological analysis of an area of 220 km(2) in t he calcareous Alps of Lower Austria assesses the possibilities for long-ter m high-quality water supply from an Alpine shallow karst area. Geological a nd hydrogeological research quantifies dependencies of groundwater distribu tion and storage on rock types and on the fracturing of host rocks in an ar ea which is typical of large Alpine regions. Estimated water budgets show a complex linkage and significant groundwater exchange between topographical catchment areas. Deep groundwater flow mostly follows tectonic fractures w hich became increasingly permeable by karstification. Fracture architecture and preferred groundwater pathways are analysed by structural geology tech niques which support the delimitation of catchment areas and the linkage of groundwater sheds to infiltration areas. Geochemical, hydrochemical and pe dological studies assess the sensitivity of groundwater chemistry to the in put of polluted precipitation. Ion exchange during soil-water interaction l eads to significant modification of the cation and anion ratios depending o n soil type. The chemistry of soils and weathered zones strongly influences groundwater quality. The study shows the strength of interdisciplinary res earch including hydrogeology, hydrology, structural geology, pedology, geoc hemistry, soil and water chemistry, which provides integrated information o n infiltration, groundwater pathways, quantified flow, groundwater discharg e and pollution risks.