Large-scale vegetation mapping (1:10,000) was applied to obtain estimates of the hydrological properties and dynamics in catchment areas that supply water to the capital city of Austria (Vienna). Vegetation types as defined by standard relevé technique, such as alpine grassland, snow bed vegetation, and krummholz were related to habitat conditions. A GIS served as the focal exploration tool. The vegetation units show specific evapotranspiration rates, which were derived from literature on experimental research covering similar vegetation types in the Alps. Additionally, physical soil properties from field data were used to derive the specific soil water balance in relation to the mapped vegetation types. Finally, the hydrological balances for each landscape unit, as well as for the total catchment area, were presented by combining the estimates for evapotranspiration and soil water properties. The consequences of environmental change (forestry, pasturing, and climate warming) are a focus of attention for water management. Predicting general changes in vegetation patterns reveals contrasting scenarios about the consequences to be expected for the water supply of Vienna.
