Ecological status of surface waters in Austria
The ecological status reflects the quality of structure and functionality of aquatic ecosystems connected to surface waters.
Rivers
In Austria there are 2,194 running waters whose catchment area is larger than 10 km². They have a total length of about 32,101 km and are divided into 8,116 water bodies.
86 % of these running waters are natural. The remaining waters are artificial, i.e. man-made bodies of water, and considerably modified bodies of water, whose nature has been decisively modified by human interference. Due to their utilisation they cannot be brought into the “good ecological status”. As far as these bodies of water are concerned, the “good ecological potential” applies as quality objective. The values below that are summarized as “moderate or worse”.
14,2 % of the running waters are in a “very good”, 26,4 % in a “good ecological status, which means that there are only minor deviations from the “uncontaminated status”. Almost one third of the waters (30,1 %) are to be designated as “moderate”, 10,5 % as “unsatisfactory” and 4,3 % as “poor”. 2,5 % are in a “good and better” ecological potential, 11,6 % are in a “moderate and worse” ecological potential, for 0,3% there is no assessment available.
Lakes
Austria has numerous stagnant waters, like naturally developed lakes, pools, small water bodies, water bodies in flood plains.
62 lakes are big lakes with an area of more than 50 ha.
The majority of the 43 natural and 19 artificial lakes which are larger than 50 ha is in a “very good” (6,5 %) or “good” ecological status (35,5 %). 40,3 % are in “good and better” ecological potential. 14,5 % of the lakes have been identified as being in a “moderate”, 3,2 % in an “unsatisfactory” ecological status.