Indian summer on the Traisen River

LIFE+ Traisen: More than just passability

At an exchange of experiences on the topic of the Austrian National Water Management Plan I (NGP) from the Austrian Water and Waste Management Association (ÖWAV) on 12 November 2015, Prof. Mathias Jungwirth and Project Leader Roland Schmalfuß introduced the LIFE+ Traisen project. Materials from the lecture can be found here: Presentation

Serengeti on the Traisen

From the current construction activity at LIFE+ Traisen: Excavation works are currently being carried out on the eastern construction section of the Traisen project. The explosive ordnance clearance has in the meantime reached the Danube delta. The floodplains are prepared for the last excavation, after which the bodies of water will fill with ground water. By the end of 2016, the project should by and large be complete.

The new entry in flow, the VERBUND blog, offers summer impressions of the dry grasslands on the Traisen.

LIFE+ project: New Traisen

Plain to see: the Au is reclaiming the Traisen river

The broad-bodied chasers have arrived

To kick off this year's swimming season, the broad-bodied chaser is making an appearance at the new Traisen. This is not a particularly athletic bathing guest, but a type of dragonfly. The broad-bodied chaser is part of the Libellulidae family and has already settled in the shallow waters on the edges of the new Traisen. This type of dragonfly with the Latin name "Libellula depressa" is very good at flying and can reach high velocities. It hunts insects while in flight. Its flattened abdomen is typical and the reason for this dragonfly's name. Males have a light blue abdomen while in females it is light brown to olive coloured.

The broad-bodied chaser is fairly common and is usually found near new, shallow waters. Even though the broad-bodied chaser is not a particularly extraordinary type of dragonfly, its appearance just shortly after construction has been completed is a very good sign. It shows that nature is beginning to take hold of the riverbed of the new Traisen.

LIFE+ Traisen: Biotope for broad bodied chaser

broad-bodied chaser (Photo: Kaufmann)


Explosive Ordnance Clearance around the Traisen

Before the digger used for the new Traisen riverbed can strike the ground, the construction site first has to be cleared. Unfortunately, quite a number of unpleasant surprises are still hidden away: explosive witnesses to the last days of the Second World War, which must be painstakingly retrieved and disposed of.

Workers at the renaturation of Life+ Traisen

Employees of the Schollenberger company at the site searching for explosives.

Sustainability-Audit at the Altenwörth Power Plant

In March 2014, our sustainability auditors visited the "Traisen" LIFE+-Project. The auditors were above all interested in the compliance with the conditions from the UVP notification and in capturing of the sustainability data for the report. A photographic report on the on-site inspection at the construction site can be found on flow, the VERBUND blog.

Safety First - A Tunnel for the Danube Cycle Path

Anybody operating a large-scale construction site has to be considerate of many interests. Above all, the project goal must stay in the foreground, cost calculations have to be adhered to and all interests, from nature protection to tourism, catered for. The way this is done is demonstrated in the LIFE+ Traisen project, Austria's largest renaturation project to date.

Pictures and details available in the

November 2013: BOKU Local Inspection of the Floodplain

Just in time for the start of winter, university professor Matthias Jungwirth from the Vienna University for Natural Resources and Life Sciences visited the project area with students. The co-initiator of the project makes no secret of his joy: "For Austria and especially Lower Austria, which has the highest density water body related EU-Life Projects in Europe, the project in Traisen represents a further opportunity to maintain its leading role in the development and execution of projects in the field of river revitalization on large rivers", says Professor Jungwirth in his report. (PDF)

Students working at the LIFE+ Traisen project

Renaturation Project at the Altenwörth Power Plant

In the "Mid-West" section of the construction, excavators and trucks are bustling about. On a specially fortified construction road, separated from the Danube cycling path, they will bring gravel, topsoil and sediment from the floodplain or distribute them onto the floodplain. Everything is being carried out according to a detailed plan, whose goal is to create foundations for a new Traisen river. Starting in 2019, this section of the river will be left alone for subsequent years. Flooding will create new pools, meanders, silt deposition areas and scouring areas. It will be "A miniature Amazon", as project coordinator Helmut Wimmer points out.

The gravel dredged up for the new course of the river will be brought to the Danube using the shortest route and from there, will be transported away by ship. The gravel will partly be used for the construction of new spawning grounds for fish in the Danube and partly be put back in the section of the Danube downstream from Vienna. The river there is deepening from year to year and the gravel from the Traisen is sorely needed.

Traisen LIFE+ 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.

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Helmut Wimmer project 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.

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.