View of the Traisen. The narrow river runs through a small wood in the sunshine.

The LIFE+ Traisen project:
a retrospective

After three years of construction, Austria's largest renaturation project on a watercourse has been completed. Under the title "EU-LIFE+ Traisen", VERBUND and its partners transformed the previously straightened estuary area of the Traisen over a length of 9.4 kilometers into a diverse floodplain landscape.

Find out more about the progress of the LIFE+ Traisen renaturation project by VERBUND and partners at the Altenwörth power plant on the Danube.


Local inspection of the new Traisen

Apart from a few remaining works, the construction measures for the LIFE+ Traisen project have been completed. The new floodplain in the estuary near the VERBUND Danube power plant in Altenwörth is thriving. During a site inspection, Mayor Marion Török (Zwentendorf) and Mayor Wolfgang Benedikt (Kirchberg am Wagram), together with plant group leader Heinz Allmer and project manager Roland Schmalfuß, saw for themselves the unique development of a lively river landscape between the Danube and the Traisen.

Heinz Allmer (VERBUND), Wolfgang Benedikt (Kirchberg/W.), Marion Török (Zwentendorf), Anton Kühtreiber (Zwentendorf), Roland Schmalfuß (VERBUND) met at the mouth of the LIFE-Traisen.


Experts confirm ecological success on the Traisen

The restoration of the Traisen estuary is Austria's largest renaturation project to date and one of the most comprehensive measures in all of Europe. Two years after the completion of the works, ecologists are examining the success of the measures. Using electro-fishing and modern technology, researchers from the Universität für Bodenkultur prove the sensational success. A trophy Danube salmon measuring 113 cm in length is one of many pieces of evidence that fish have already colonized the new Traisen.

With the renaturation of the Traisen, fish diversity also increased again: a Huchen with a length of 113 cm was sighted in the LIFE+ Traisen project area. The fish is held by Thomas Friedrich.


The LIFE+ Traisen project is complete!

With the ceremonial planting of the last tree on October 14, 2016, the LIFE+ Traisen project was jointly concluded by the project partners. The newly created floodplain landscape will now be left to nature. The project and details of the plant were presented to local residents at the Altenwörth power plant site as part of an open day.

After three years of construction, Austria's largest renaturation project on a watercourse was completed today: This was celebrated by planting the last tree of the project together.

In the meantime

A lot has happened during the renaturation project on the Traisen. Read about the first successes of the project here.

A view of the Traisen from above. Numerous water birds, including many swans, make their way along the renaturalized river.

The renaturation of the Traisen has boosted wildlife. Thanks to the project, the 9.4 km long riverbed has been transformed back into a floodplain landscape.

The renaturalized Traisen in 2021: A river meanders through a small forest.

The Traisen estuary is currently being renaturalized. The straightened Traisen is being transformed into a natural floodplain landscape over a length of 11 km.

A view of the construction site around the Traisen in 2014. A river bend is being dredged.

LIFE+ Traisen project: VERBUND cleans up the Traisen - removal of material from the Second World War. Safety first: Even an aerial bomb was found.


BOKU on site inspection in the floodplain

Just in time for winter, Prof. Mathias Jungwirth from the Vienna University of Natural Resources and Life Sciences visited the project area with students. The co-initiator of the project makes no secret of his delight: "For Austria, and Lower Austria in particular, which has the highest density of water-related EU Life projects in Europe, the Traisen project is a further opportunity to maintain its pioneering role in the development and implementation of river revitalization projects on large rivers," said Prof. Jungwirth in his letter.

The renaturation program at the Traisen river showed its progress. You can see an alluvial pond with reeds.

A project begins ...

renaturation project requires well thought-out planning and a targeted approach. Find out more about the first steps in the LIFE Traisen project.

LIFE+ Traisen project progress in June 2014: The middle-west construction section is complete. The meandering of the river is clearly visible.

LIFE+ Traisen: A detailed expert plan is now set to turn the Traisen back into a river. The first construction phase was opened at the beginning of July 2014.

A view of the construction site around the Traisen in 2014. Excavation work is being carried out at the Feldwegbrücke..

LIFE+ Traisen: Sustainability audit at the Altenwörth power plant - the focus is on the requirements of the EIA decisions and the collection of sustainability data.

A view of the construction site around the Traisen. A first river loop has already been implemented.

LIFE + Traisen: Start of construction: Over the next years, a straightened section of river will be transformed into a dynamic and diverse floodplain.


Interview with Project Manager Helmut Wimmer, VERBUND Hydro Power AG

What makes the Traisen LIFE + project so special?

So far, Traisen LIFE+ is Austria's largest renaturation project. The Traisen estuary, which, during the construction of Altenwoerth Power Plant, was relocated and straightened out, will receive a completely new riverbed in a new floodplains setting. This will take six years, until 2019, and will cost 26 million Euro, of which VERBUND will account for 12 million and the rest will be contributed by EU funds and partners from the Austrian government and the province of Lower Austria.

Will mistakes made in the past be rectified here?

When planning the Danube power plants 40 years ago, other factors stood in the foreground. The main focus was the direct benefit for mankind: electricity generation, flood protection, expansion of agricultural areas, in other words, the priorities were different. Today we know more, including the value of a diversity-rich landscape. Examinations for the environmental impact declaration of the project have revealed that the current flora and fauna existing in today's floodplains is amazingly rich in diversity. This is the premise of the Traisen LIFE+ project.

This won't generate a single additional kilowatt hour of power, so why all the effort?

As operator of the Danube power plants, VERBUND has a responsibility vis-à-vis the environment. For a long time the renaturation of the river Traisen has been a goal of many initiatives, which is now being boosted by VERBUND as a strong partner and good neighbour. The Traisen LIFE+ project is no individual case. The efforts are well worth the while: 30% of the sites housing VERBUND power plants were placed under nature conservation after construction of the plants.

What constituted the greatest obstacles?

We had to convince the local residents that we were neither mining gravel nor erecting a flood protection dam but intended to establish an ecological flagship project. As such, we were dependent on the support and approval of all landowners the floodplains. After all, the project is to benefit all stakeholders, from citizens wanting to enjoy the floodplains' biodiversity for recreational purposes to fishermen and hunters to forestry operations. And I especially want to applaud the collaboration with the authorities in charge.

How will things progress from here?

When felling trees in the floodplains, we are bound by nature's cycle: Only in winter and spring may trees be felled. Over the period of the next six years, the Traisen will, little by little, receive a natural course. From then on, the landscape will be shaped by the river in accordance with its natural cycle. The first construction measures are currently being initiated. Following the clearance, the construction site will be examined for relics from the war era, cycle path detours and the necessary construction paths will be established, and only then will the actual excavation work begin.

Interview LIFE+ Traisen with project manager Helmut Wimmer, who is interviewed by ORF. He speaks into a microphone and the camera is directed at him. The interview takes place directly on the Traisen.


Breaking of the Ground for LIFE+ Traisen Project

Austria's largest renaturation project related to a hydropower plant is entering its construction phase. The estuary of the Traisen river in the area of the Danube power plant of Altenwörth is thus converted from a regulated river to an ecologically diverse floodplains landscape. 

The Traisen currently runs in a regulated bed, which doesn’t give the river any possibility to expand and which becomes further entrenched year in and year out. In the coming 6 years, specialists will enhance the course of the river and landscape it with meanders, shallow water zones and pools - in accordance with a detailed plan. "A total of some 26.5 million euro will be invested here in a unique ecological upgrade and we are delighted to have been able to win over partners from the EU, Bund and the federal province of Lower Austria," said Michael Amerer, board member of VERBUND Hydro Power AG. With 12 million euro, VERBUND is carrying the majority of the costs. The EU is largely promoting the project through financing from the LIFE+ Nature-and-Biodiversity Fund. The remaining costs will be carried by the project partners, such as the Lower Austrian Fishery Association, the Lower Austrian Landscape Funds, via donau, as well as the Federal Water Engineering Administration.

A habitat for man and nature

"The goal of the LIFE+ Traisen project is the recovery of a diverse wetlands area, which can be left to its own resources and the natural cycle," outlined Karl Heinz Gruber, board member of VERBUND Hydro Power AG. "The project complements our longstanding, successful practice of constructing and operating our power plants in harmony with nature."

A total of 30 % of the contact surface of VERBUND hydropower plants has subsequently been designated for environmental conservation. It is not only nature that benefits from the ecological diversity of the Traisen, but also the neighbouring municipalities, fishermen and tourists.

Back to nature: the Traisen river today. You can see a small wood with shrubs and grasses. The river divides the view in the middle.


New Guidelines for the Construction of Fish Ladders in Austria

It is intended that the "Guidelines for the Construction of Fish Ladders" issued by the Ministry of Life will represent support in the planning of fish ladders. It contains criteria which, with correct implementation, regular operation as well as frequent maintenance, will ensure that the fish ladders are functional and, therewith, that the upstream oriented migration of fish is largely established (again). Henceforth, the solutions to be found in the guidelines offer advantages and concrete improvements, in particular with regards to feasibility and function. Fish ladders, which are constructed in accordance with the available criteria, should also – in all probability - fulfil their function.

The "Guidelines for the Construction of Fish Ladders" has been in existence its final version since mid December 2012 and has officially been made available to the public from the end of 2012 on the homepage of the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW). With regards to the function control, the Ministry intends to develop its own recommendations in conjunction with the provinces. To enable easy location of the fish ladders, the main focus is being placed on the positioning of the entrance area, whereby sufficient guiding flow is recommended. In general, planning safety in the construction of fish ladders has been thoroughly increased. Nevertheless, a deviation from the recommendations is possible at any time. A reason for the deviation, as well as a corresponding proof of function, will then be necessary. Today, this is already obligatory in the case of medium-sized and large bodies of water.

It's worth taking a look at the floodplain landscape of the Traisen. The floodplain landscape winds through its natural habitat, delicately greened. The river is accompanied by meadows and forests.