Drava - River Widening Obergottesfeld
Drava - River Widening Obergottesfeld
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 Obergottesfeld is one of the project areas where the river was widened.
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
Obergottesfeld before and after the construction of the measures
Measures selection
At Obergottesfeld, a part of the floodplain was given back to the river. The agricultural land made way for a side channels, oxbow lakes and standing bodies of water. A tributary was also widened to give it more space during a flood event. This improved the water retention in that area, as the river was free to flood the wider floodplain. Hidden built-in breakwaters were constructed to protect the banks during floods.
Monitoring
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 were monitored during the post-monitoring program. Since it was combined with an earlier LIFE project, the monitoring for fish, macro-invertebrates, most of the river morphology was not done in Obergottesfeld since it was not yet finished. Only amphibians and the flow velocity were measured. No further monitoring results could be found for Obergottesfeld.
Expectations and Response
The exact response of the measures on Obergottesfeld are not known because the latest found monitoring report was from 2011, the same year the Obergottesfeld project was finished. It is known that the flow velocity in the main channel decreased because of the side channel and there was a high number of individuals of amphibians.
Cooperation
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.
Communication
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.
Funding
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
Contact
Name: Norbert Sereign
Role: Project leader
Organization Name:
Organization Type:
Phone-Number: + 43 14762 5301 62312
Email: Norbert.Sereinig@ktn.gv.at
References
Unterlercher, M. and Petutschnig, W. (ed.) (2011) Lebensader Obere Drau: F2. Monitoring Synthesebericht, Amt der Kärntner Landesregierung
Life vein – Upper Drau River (2011)
Website
Related Measures
- Lower river banks or floodplains to enlarge inundation and flooding
- Improve water retention
- Link flood reduction with ecological restoration
- Construct semi-natural/articificial wetlands or aquatic habitats
