The quality classes are presented by water segment. The quality classification is carried out on dammed plankton-dominated streams. It is based on the mean chlorophyll-a content over three years, for the period from 1 March to 31 October (LAWA 1996), as well as on the expected visibility depth ranges and overall phosphorus concentrations (Leibniz Institute of Freshwater Ecology and Inland Fisheries, IGB).
