Drava - River Widening Rosenheim

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Drava - River Widening Rosenheim

Factsheet: Drava - River Widening Rosenheim

Country AT
River Name Drava
Site Name Drava - River Widening Rosenheim
River Characterisation
    River typology
    Location (Lat Lon) 46.8237912649146, 13.391432762146
    Altitude mid-altitude: 200 - 800 m
    Catchment area very large: > 10000 km2
    National code/
    River type name
    Hydromorphological quality elements

    Biological quality elements
    Ecosystem Services
    EU Directives
    Project size 1 km
    Approximate costs > 1 000 000 Euros
    Synergy Flood protection, Ecology, Recreation
    Status Realised
    Period of realization 2006 - 2011
    Evaluation Hydromorphological and ecological changes
    Implemented by Federal Ministry of Agriculture, Forestry, Environment and Water Management

    General description

    The Drau river is the fourth longest tributary of the Donau with a length of 707 km. The source of the river is in the Italian municipality Toblach where it continues its flow through Austria, Slovenia, Croatia and Hungary. The mouth of the river in the Donau is near the city of Osijek.

    The Upper Drau in Austria is an European protected area with the largest grey alder riparian forests of Austria and over 140 species of birds, including 51 red-listed species. The LIFE project ‘Life vein – Upper Drau River’ was carried out to counteract the trend of too narrow channels that are vulnerable for erosion and flooding by widening the river. Location Rosenheim is close to a town of Drauhofen, St. Gertraud and Rosenheim.

    Pressures and Drivers

    The Upper Drau is the last free-flowing, not dammed stretch of the river Drau. Nevertheless, human activity has changed the river and its floodplains. When a rail road line was build through the valley in 1870, regulatory procedures were carried out in order to reduce the flood danger and to expand intensive agricultural lands and settlements. The embankments created a narrow channel which suffered from bed erosion. The river bed deepened and wetlands and agricultural lands went dry with the sinking groundwater level. The stability of bank protection structures also suffered from the erosion.

    Global objectives

    The project has 4 global objectives

    • Further stabilization of the Drau river bed through widening and strengthening of bed load influx from tributary brooks.
    • More pristine, dynamic shaped river habitats
    • Improved information and visitor management on site
    • International cooperation with the respective authorities of the Drau neighboring states

    Specific objectives

    No specific objectives could be found in the available project documents

    Success Criteria

    No success criteria could be found in the available project documents

    Site description

    Rosenheim before and after the construction of the measures Rosenheim before after.JPG

    Measures selection

    At location Rosenheim (see figure above), a new side channel (1) and wetland ponds (5) were constructed. The side channel was fitted with steep banks on one side of the channel (3). An dead side channel was reconnected to the Drava (2) and a gravel bank was made (4).


    Pre-restoration monitoring

    A pre-restoration monitoring scheme was carried out to assess the current state of the location. The monitoring focuses on:

    • Habitats and animals on the Habitat and Birds Directive
    • Fish (presence of species and number of individuals)
    • Carabid beetles and other macro-invertebrates (number of species)
    • Amphibians (number of individuals)
    • River morphology (soil depth and flow velocity)

    Post-restoration monitoring

    The same indicators used in the pre-restoration monitoring were monitored during the post-monitoring program in 2010 and 2011.

    Expectations and Response

    It was expected that new habitats would develop by the natural dynamics in the widened river section. The animal species would benefit from the new aquatic habitats. At the same time, the flood protection was improved by bank stabilization and a higher retention area.

    Ecology The synopsis of the monitoring carried out in 2010 and 2011 do not show the monitoring results for the location Rosenheim for fish. The results of the monitoring for the combined projects of the LIFE project and the older GBK Obere Drau project show that the Grayling (Thymallus thymallus) has increased considerably with a doubling of the caught biomass, but it is still below the values measured in the end of the 1980s. Two species that show no improvement are the Danube salmon (Hucho hucho), which is close to complete extinction in the Upper Drava and self-sustaining reproduction could not be determined. The presence of common nase (Chondrostoma nasus) could only be determined by few individuals, but the population has not improved.

    Also for macro-invertebrates no results for the individual project Rosenheim were presented in the synopsis, but for all the projects 5 new species of spider and 8 species of carabid beetles were found of the total 130 species. One of these species was the spider Arctosa cinerea, a species strictly related to gravelly-sandy river banks and nearly extinct in Austria. In Rosenheim, a new population of a few individuals was sighted.

    The number of amphibian species rapidly increased from 3 to 6 species with numerous sightings of adult Yellow-Bellied Toad (Bombina variegata). Close to location Rosenheim, slow worm (Anguis fragilis), grass snake (Natrix natrix) and Aesculapian Snake (Zamenis longissimus) were sighted.


    In Rosenheim, a sediment deficit is prevalent, causing deepening of the soil of 12 cm. This is less than when the old state of the river (29 to 23 cm). Only a small extent of the dynamic morphological processes took place at Rosenheim, due to the low sediment input into the widened section. This reduces the effectiveness of the measures. A reason for the high sediment deficit could be the tributary of the Möll river upstream. The tributary enlarges the discharge of the Drava, but does not transport the needed sediment.


    The project was carried out by the Federal Ministry of Agriculture, Forestry, Environment and Water Management in cooperation with the Carinthian State Government and Torrent and avalanche control, section Carinthia.

    The main stakeholders were the land owners of the agricultural lands bordering the Drau river.


    The communication with stakeholders and the general public was diverse. The project was opened with a large ceremony with a large attendance from the general public and politicians. A total of 70 project team meetings, 13 action days and 25 excursions were carried out.


    Approximate cost (total project): €4,600,000

    %EU Funding: 32.5 (€1,500,000)

    %State: 58.5 (€2,600,000) Federal Ministry of Agriculture, Forestry, Environment and Water Management

    %Regional authority: 4.5 (€200,000) Carinthian State Government

    %other partners: 4.5 (€200,000) Torrent and avalanche control


    Name: Norbert Sereign

    Role: Project leader

    Organization Name:

    Organization Type:

    Phone-Number: + 43 14762 5301 62312

    Email: Norbert.Sereinig@ktn.gv.at


    Unterlercher, M. and Petutschnig, W. (ed.) (2011) Lebensader Obere Drau: F2. Monitoring Synthesebericht, Amt der Kärntner Landesregierung

    Life vein – Upper Drau River (2011)



    Related Measures

    Related Pressures