River typology – the basis of river assessment
River assessment is based on river type-specific reference conditions. The more a river stretch is deviating from the reference condition, the worse is its ecological status.
Thus, a river typology has been developed for Germany, presently comprising 24 river types:
4 types in the Alps and in the pre-alpine areas
8 types in the lower mountainous areas
8 types in the lowlands
4 types occurring in different ecoregions