The Integrated River Engineering Project on the Danube East of Vienna is an integrated overall project intended to improve fairway conditions on the Danube section east of Vienna by means of river engineering measures (river bed adjustments and regulation structures such as groynes and guide dykes) – excluding weirs – taking special account of the ecological requirements of the Danube Floodplain National Park.
 

Currently, the free-flowing section of the Danube between Vienna (Freudenau power plant) and the Austrian-Slovakian border (river kilometres 1921.0 – 1872.70) constitutes a substantial weak point in inland waterway navigation and is characterised by a continued bed erosion rate of 2 to 3.5 cm per year.

On the one hand, insufficient fairway depths strongly fluctuating over the year significantly restrain the reliability and competitiveness of inland navigation in this section of the Danube, and on the other hand, the continued deepening of the river bed has a sustainable negative impact on the ecological balance of the Danube Floodplain National Park.

Therefore, the Federal Ministry of Transport, Innovation and Technology (bmvit) and via donau – Österreichische Wasserstraßen-Gesellschaft mbH initiated the “Integrated River Engineering Project on the Danube East of Vienna” in order to improve fairway conditions and ecological deficits in this section of the Danube.

Because of its comprehensive and interdisciplinary project approach, the “Integrated River Engineering Project on the Danube East of Vienna” constitutes an important step to cope with growing transport volumes in the Danube corridor in an environmentally and socially friendly way and may serve as a model for the elimination of further, similar bottlenecks along the Danube.

In order to accomplish the project goals, it is planned to implement a combination of different river engineering and ecological hydro-engineering measures in this section of the Danube:

• Granulometric river bed stabilisation  
• Low water regulation
• Riverbank renaturation
• Waterway linkage
• Navigation-related measures

A major goal of the project is the stabilisation of the river bed. The heavy bed erosion of the last few decades can be counteracted by means of granulometric river bed improvements. It is planned to add coarse gravel with a grain diameter of approx. 40 to 70 mm, which is coarser than the major part of the Danube’s natural bed load, but finer than the maximum natural grain size. The thickness of the gravel layer and the exact grain size (grading curve) are the results of an optimisation task, whereby nautical and ecological requirements have been taken into account. The grain size distribution of the material to be added was determined in such a way that, with an appropriate safety distance, damage to ship propellers can be avoided and that the ecological exchange capacity of the river bed of the Danube is preserved.

The major project goal in terms of inland navigation is to secure adequate fairway conditions at low water levels. This will be accomplished by means of low water regulation measures (groynes and guide dykes). The distance between groynes, their heights and shapes were optimised from an ecological, nautical and material-efficient point of view in order to minimise the deposition of sediments in the groyne fields and the formation of scours near the groyne heads.

The major ecological goal of the project is to give the river greater freedom to move and thus to enhance the ecological functioning of the region. The landscape-forming power of the river is to be reinforced – primarily by riverbank renaturation. Protection structures on slip-off slopes are removed, undercut slopes are preserved. Furthermore, the waterway linkage is to increase the exchange of water between the Danube and the floodplains and will bring flowing water into the floodplains. Side arms will be linked to the main river at low water level.

One of the navigation-related measures of the project is the relocation of certain sections of the existing navigation channel, so that scours and other deeper zones can be used for navigation purposes and more shallow zones can be avoided.

 
The obligation to carry out an Environmental Impact Assessment for the Integrated River Engineering Project is derived from Annex 1 to the 2000 Environmental Impact Assessment Act. Pursuant to these provisions, an Environmental Impact Assessment is required for newly constructed and modified protective and flow-control structures with a construction length exceeding 3km along running waters with a mean flow rate of more than 5 m³/s. Measures to improve the ecological functioning of waters, i.e. so-called re-naturalisation measures, constitute the only exception.

In order to apply for an Environmental Impact Assessment the project applicant files an Environmental Impact Statement (EIS) with the competent authorities.

• via donau has been entrusted by the Austrian Federal Waterways Act with the planning and implementation of the Integrated River Engineering Project.

Financing

• Federal Ministry of Transport, Innovation and Technology (bmvit)
• EU funding under the TEN-T programme

Project volume

• Total costs: approx. 220 million € (index: 2006), subject to cost changes through authority procedures

Project schedule

• Establishment of an interdisciplinary steering committee: beginning of 2002
• Examination of alternative and variant solutions: 2002 – middle of 2004
• Moderation procedure to ensure public participation: middle of 2003 – middle of 2004
• Preparation of the Environmental Impact Statement (EIS): end of 2004 – beginning of 2006
• Conduct of the Environmental Impact Assessment (EIA Basic Authorisation): beginning of 2006 – presumably 2010
  • Public inspection of the EIS: December 2007 – January 2008
  • Public hearing: October 2008
  • Summarising Assessment: June 2009
• Model testing: beginning of 2004 – end of 2008
• Performance of 1:1 pilot tests
  • Pilot Project Witzelsdorf: construction works: end of 2007 - middle of 2009
  • Pilot Project Bad Deutsch-Altenburg: construction works will start presumably 2010
• Main works: start of construction works along the whole section after the EIA procedure (general and detail authorisation). construction period: 8-9 years

Contact

via donau – Österreichische Wasserstraßen-Gesellschaft mbH
Dieter Pejrimovsky, Head of the Integrated River Engineering Project Team
dieter.pejrimovsky   via-donau.org