Abiotic stream classification as a basis for a surveillance monitoring network in Austria in accordance with the EU Water Framework Directive

This study presents the 26 major surface water types established in Austria in accordance with the draft of the EU Water Framework Directive (WFD). Th ese types are made up of so-called aquatic landscape units and large rivers . The 17 aquatic landscape units were defined using a database in which all Austrian running waters with a catchment area greater than 10 km(2) were d escribed according to the following typological features: size of catchment area, altitude of catchment area and confluences, stream order, geology, z oogeographical regions (ecoregions), and subregions. At running waters with gauges, a classification according to flow regimes was carried out. Large rivers were defined as running waters with a stream order greater than or e qual to 7 and/or a catchment area >2500 km(2) and/or with an average flow > 50 m(3)/s. These major types represent, inter alia, the basis for the estab lishment of a surveillance monitoring network as required by the WFD.