unbekannter Gast


Rivers and Streams, Biological Quality of: Running bodies of water in Austria are biologically assessed with the saprobic system, which is based on the interconnection between water pollution and the increase in the amount of certain organisms present in the water. Bodies of water are graded in four classes, shown by different colours in the Water quality maps which have been published since 1968 by the Ministry of Agriculture: Class I - hardly polluted (blue), class II - moderately polluted (green), class III - considerably polluted (yellow), class IV - extra-ordinarily polluted (red). In the past two decades water quality has improved significantly due to purification plants, in particular as regards poorly biodegradable and toxic substances.