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Breitenfurt bei Wien, Austria

Summary: River basin management is faced with the interesting challenge of having to bring the requirements of the EU Water Framework Directive (WFD), the EU Floods Directive (FD) as well as the EU Flora-Fauna-Habitats (FFH-)and Birds Directives into functional harmony. The main point is to reconcile the objectives and evaluation standards as well as the principles of deterioration prevention and ecological status enhancement (WFD) through an integrated planning approach. The focus of the programme of restoration measures for the River Enns, a tributary to the River Danube in Austria, is on the medium and long term development of the river landscape, while considering the present requirements under the Water Framework Directive, as e. g. (1) requirements for the programme restoration through the National Water Management Plan, (2) allowance for the results of the water status surveys, (3) existing protected areas as well as nature reserves to be considered, and (4) requirements of civic participation. Planning is being based on the principle of integrating top-down and bottom-up approaches. The measures to be taken for achieving the water-body objectives are conceived as smallest planning units to be aggregated in spatial steps to form a comprehensive programme of measures. Supra-regional objectives in turn, such as the connectivity of river systems as provided under the National Water Management Plan, are being scaled down to the local level. Similar to other rivers, the process-oriented, dynamic "revitalisation approach" of the Water Framework Directive is up against a protection requirement of a more static nature with respect to a large number of animal and plant species (subjects of protection under Annex II of the Habitats Directive). This tends to generate potential conflicts in the landscapes of the River Enns, especially for those planned hydro-morphological measures which are intended to admit or re-initiate dynamic processes in the water body, including integration of as many surviving remnants of the former river landscape as possible. By contrast, in terms of nature conservation, priority should be given to the preservation of certain species or habitat types worthy of protection. Problem solving approaches for coping with these, to some extent conflicting, development objectives are illustrated with examples. Potential impacts of the suggested measures on the hydro-morphological quality components according to the Water Framework Directive are discussed and compared with the effects of the measures on the Natura 2000 subjects of protection. This systematic synopsis forms the basis for the development of management scenarios. © 2011 Springer-Verlag.

Schmutz S.,University of Vienna | Wiesner C.,IHG | Preis S.,IHG | Muhar S.,IHG | And 2 more authors.
Osterreichische Wasser- und Abfallwirtschaft | Year: 2011

Summary: There are at present 29 power stations on the River Mur in Styria. The impounded sections account for 26 % of the river and 11 % is diverted (with flow left in the river bed). A satisfactory hydro-morphological condition is still found in about 25 % of the river course. Major free-flowing sections have survived between the boundary with the province of Salzburg and the confluence of the Mur with the River Mürz near the town of Bruck. The population of Danube salmon in the Mur is still capable of independent reproduction and is accorded a high protection priority at an international level. But having now declined to an adult population of 1,500, the Danube salmon in the Mur has dropped below the critical limit of minimum population sizes deemed capable of survival in the long term. Partial populations of more than 100 adults are found only in major free-flowing sections, mainly upstream of the town of Leoben above Bruck. Disappearance of the Danube salmon in a section qualified as having a good status in terms of the FIA system of analysis would degrade this section to moderate quality. Impounded river sections are generally severely deficient in species diversity and fish ecological quality (Fish Ecology Class 4 to 5). The good to very good status is found in 89 % of the natural free-flowing sections, while only 77 % of the residual-flow sections have a good status. As the percentage of impounded and residual-flow sections increases, the fish ecological quality declines. © 2011 Springer-Verlag.

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