Impoundment Höchstädt (river-km 2538.0-2530.8) in the upper reach of the Danube River in Germany
Pall, Karin; Janauer, Georg A.
Numerous hydro-electric power stations and their retainments form a characteristic feature of the upper reaches of the River Danube in Germany and Austria. The aquatic vegetation was assessed in one retainment, which is part of a contiguous set of five power plants. Three reaches were recognised in the impoundment based on characterstic species. In the upper part only rheophilic mosses and Ranunculusjluitans were present. In the middle reach one moss is still present and several new phanerogam species occur, but the plant mass is low. In the lower reach no mosses are present any more and phanerogams become very abundant. Upon comparison the latter situation is close to that found in reaches of the Danube (e. g. in Hungary) where the natural gradient of the river is much lower than in Germany.