During the 19th Century the Danube was regulated to improve it for shipping. Originally it was an ever-changing environment with many side arms. Through dams at the river banks, side arms were split off and floodplains dried out. In Austria a series of 10 hydroelectric power stations were erected since the 1950s, basically converting the flowing river to a series of reservoirs. These hinder the migration of animals as well as the flow of sand and gravel downstream, making the Danube a bit deeper each year.

The two last free flowing sections of the Danube in Austria are the Wachau region about 50km west of Vienna and the floodplain forests east of Vienna. Floodplains are an ever-changing habitat with new gravel and sandbanks being created by the river, and are slowly overgrown first by bushes and then trees. Other areas are eroded by the river.

The floodplain forests lie at the border between Atlantic (mild and wet) and Pannonian (warm and dry summers, cold and dry winters) climates, making them a habitat for a diverse ecosystem. There are banks of rubble, which today are rare at the Danube.

The Hainburg Dam

In 1984 work began to build a 16m-high dam in the Danube about 30km downstream from Vienna in the middle of a floodplain forest at the town of Hainburg. The course of the river was supposed to be changed by 2km. The operators of the Danube hydroelectric power stations (most shares owned by the state and the largest producer of power in the country), industries and unions approved of this plan due to rising demands in electric power.

In addition to producing power, the dam was also supposed to be part of a system of weirs and locks, which would have made shipping for large cargo ships on the Danube independent of water levels - this was a requirement of a convention signed between all the nations at the Danube, most of which were behind the Iron Curtain¹ at the time.

Inhabitants of Hainburg were in favour of the new power station; although realising the plans would have meant flooding part of their town, they hoped for new work opportunities and tourism at the reservoir.

Environmental activists on the other hand tried to fight it by any means. Political discussions about the dam were ongoing from 1983.

In May 1984 a group of politicians and journalists initiated the 'Konrad Lorenz Volksbegehren', a petition for the saving of the floodplains. It was planned to be open for signing in March 1985. One of their figureheads was Konrad Lorenz, animal behaviour scientist and Nobel laureate. To advertise for their petition they organised a 'press conference of the animals', where people dressed up as animals of the floodplain explained their view on the dam. This actually managed to increase resistance and protests against the project.

The politicians in power, however, did not care about any of this and continued with their plans to build the dam at the Danube. When even a report for environmental sustainability by the province Lower Austria argued in favour of the project, activists peacefully occupied their government building on the next day.

In early December 1984, thousands of people protested in the streets of Vienna. Shortly after, the first trees fell on the floodplains. Environmental activists, especially students but also prominent people, packed their bags and made their way to the forest. They tried to block the loggers' way and occupied the area. Tents were put up in the snow at freezing temperatures. At times over 2,000 people were on-site. Barricades were erected on the roads, which actually managed to stall the clearing of the forest.

Politicians still were not impressed; they did not want to wait until March, when the public petition was scheduled to be discussed in parliament. The police were sent out to protect the loggers and get rid of the activists, who were threatened with prison and monetary fines. Still, the activists went on literally hugging trees to protect them.

Activists even managed to storm a TV gameshow that had the Austrian chancellor as a guest, and showed a poster which advertised their cause. The game master allowed them to give a short speech.

On 17 December, unions threatened to remove activists themselves if the police did not do it. Two days later the police came with about 300 men to clear the floodplain forest of about 3,000 activists. Batons were used. As word got round about this through the media - who condemned the police's actions - 40,000 people demonstrated on the streets in Vienna. The church called for peace at Christmas. Pressure got too much for the politicians, who decided to stop the clearing for the foreseeable future.

Many activists still spent Christmas in the forest and stayed until January, when the supreme administrative court decided to halt all actions until all legal complaints were settled. In March 1985, finally, the public poll brought an end to the project. The dam would not be built.

This was only six years after the negative poll about the atomic power plant in Zwentendorf, Lower Austria, and over 10 years after plans for a hydroelectric power station in the Wachau region were also given up due to severe protests². In 1986 the Green Party - which of course worked with the activists - managed to get into parliament for the first time.

Soon the idea came to protect the floodplain forest by creating a national park. Fishermen, hunters and boat owners especially had to be convinced of this idea, and it took until 1996 when politicians finally signed all the papers.

The Nationalpark Donau-Auen

The Nationalpark Donau-Auen encompasses an area of over 9,600 hectares around a 36km length of the Danube between Vienna and Bratislava (Slovakia). The water levels rise and fall up to seven metres.

Today over 5,500 species of plants and animals live in the national park. For many it is their biggest sanctuary. It is the largest breeding ground for the little ringed plover and other birds which nest on gravel. There are also white-tailed eagles and kingfishers. The Nationalpark Donau-Auen is home to Europe's last healthy population of the European pond turtle. Most of Austria's species of fish and amphibians can be found here. The European mudminnow fish was believed to be extinct in Austria until it was found again in the floodplains in the 1990s. There are also many endangered species of plants.

Regular floods are essential in the floodplains as they create environments like gravel banks and heaps of driftwood, which are inhabited by specialised species. Endangered trees are part of the forest. On dry gravel plains there are orchids and other drought-resistant plants.

The Nationalpark Donau-Auen is a popular recreation area for people from Vienna and Lower Austria. There are many paths for walking and riding bicycles. The national park also organises tours by boat and other guided tours. Bordering the national park in the south is the archaeological park Carnuntum. An information centre can be found in Orth an der Donau, approximately in the centre of the national park.

Today the national park doesn't fight against loggers but does fight invasive animal and plant species, which bring imbalance to the ecosystem. Dams further up the Danube prevent gravel being washed down to the floodplain, which makes them lose ground. This makes it necessary to mechanically add gravel from time to time. Also, climate change leads to sinking water levels on the floodplain, therefore an old arm of the Danube was reunited with the river to add more water.

The Nationalpark Donau-Auen is part of a network of environmental protection areas along the Danube that work together to protect nature along Europe's second-longest river.