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populations. It took a relatively long time to realise the impact: while in the first half of the 20th century, the
focus during the construction of power plants was the impacts on fishery, since the 1980s and 90s, attention
has shifted to the ecological functionality of water bodies. The importance of diverse species and stable
ecosystems is now widely known.
The effects of hydropower utilisation can be minimised with sophisticated measures. By building functional
fish passes, for instance, the fish are given the opportunity to navigate the barriers and continue
their travels as usual. At the same time, humans can still benefit from the use of water in power
generation.
“Networked river systems” is of critical importance with regard to repopulating revitalised areas, genetic
exchange and balancing out the population flow. Apart from fish migration, it also facilitates the migration
of other species.
While fish passes were built for some older hydropower plants, they were designed with the interests
of fishery in mind. Over the last 20 years, fish passes have been created with the assistance of environmental
experts. Today, it is known that some of the measures taken years ago do not comply with
the latest findings of research. Thus, numerous projects have been launched to improve fish passes in
cooperation with scientists. The findings will be implemented in new and existing power plants.
Fish passes require a great deal of time and expenditure: they need sufficient space and generate higher
maintenance costs due to their need for regular care and adjustments to the channels.
Our brochure on fish passes (published May 2008) is available on our web site www.verbund.at >
Company > Structure > Hydropower > Portrait.
Further measures to minimise the effects of hydropower plants include the design of the power plants’
surroundings based on ecological factors, such as building shallow-water areas and additional bypass
channels. The near-nature fish passes also provide a habitat for other fauna and flora.
CURRENT VERBUND PROJECTS
The estuary of the Traisen will be scaled back to about 12.5 kilometres in length so that it rejoins the
Tullnerfelder Au. This will regenerate typical Au biotopes while ensuring fish can migrate. This EU
project is being sponsored by the state of Lower Austria and via-donau from 2009 to 2014. For more
information, please see www.life-traisen.at
In cooperation with the state of Lower Austria, the EU-LIFE project “Donau-Ybbs Network” aims to link the
section of the Danube in the Wachau region with the upper end of the reservoir of the Melk power plant and
the estuary of the Ybbs.
In the Melk reservoir, Verbund added on a fish pass – a near-nature creek, two kilometres long and an
average of 12 metres wide. The walls are made of clay; the river bed was created with stones, wood and
gravel. Construction work concluded by planting a select mix of plants and about 5,000 willows. In 2009,
40 species were already identified by monitors from the University for Natural Resources and Applied
Life Sciences.
The reconstruction of the Ybbs estuary to the Danube is Lower Austria’s contribution to the project,
helping to restore the area as far as possible to its original condition before the regulation. The new side
channels and shallow water areas means the area can reclaim its role as a “nursery” for many types of
fish. For more information, please see www.life-donau-ybbs.at
2010 – THE YEAR OF BIODIVERSITY | SUSTAINABILITY REPORT 2009 | 25
INTERCONNECTING RIVER
SYSTEMS AND CREATING
HABITATS
EU LIFE + PROJECT "HABITAT –
ESTUARY OF THE TRAISEN RIVER
FISH PASS AT MELK POWER
PLANT ON THE DANUBE