Ruppoldingen power station – environmental monitoring of success

The power station at Ruppoldingen, near Aarburg, was constructed as a showcase example of environmentally compatible utilisation of hydro-energy. A first appraisal of the project’s success has now been published in a report, which concludes that the environment has benefited from the rebuilt power station.

Positive environmental effects confirmed

Various independent experts investigated environmental developments between 1995 and 2002, comparing the pre-construction situation with the area as it stands today. Nature and the landscape, fish stocks and aquatic ecology, river flow, agriculture and ground water all received special attention on two main counts: the impact on nature, the landscape and aquatic ecology caused by rerouted waterways around the power station, and the new power station’s effects on ground water and agriculture.

The report showed very satisfying results. Numerous substitution and compensation measures implemented during construction of the power station have significantly increased the quality of the landscape in general, and certain aspects like the new bypass watercourse were classified as having a very strong impact. There have also been positive effects on bird life: the number of species has risen from 35 to 47, a 34 percent increase. The number of breeding sites has also increased by 20 percent. Especially notable is the rare kingfisher, which continues to breed in Ruppoldingen. Three firm nesting sites existed in 2002, compared to just one in 1996. Another very significant ornithological event is the recent arrival of the lesser ringed plover.

Rebuilt the power station caused major upheaval to the riverbed. The current is still causing large sediment drifts, which makes it difficult to interpret the results. Field data shows no change in the aquatic invertebrate population, even in the water storage area. An outstanding feature for the fish population is the newly constructed bypass waterway, which has developed into a worthwhile habitat with a dense and diverse ecosystem. Species diversity is even greater than in the river Aare, where revitalised tributaries have brought about the expected success.

Not only the fauna, but also the flora and vegetation benefited from the power station construction project. Between 1995 and 2002, the number of recorded species increased from 213 to 306, including six protected species – up from just two previously. The building of the new power station encouraged the growth of typical riverside meadow plants and created new habitats. Declared objectives have been met, and this positive trend can be expected to continue over coming years. Natural development will cause further shifts in the range of plant and animal species.

The impact on ground water has been minor. The changed water balance had a welcome effect on nitrate levels, which fell markedly. Oxygen content decreased too, but within expectations. Topsoil added to create cultivated areas has developed well; agricultural land in particular does not become waterlogged.

The local population also benefits from this landscape improvement. Ruppoldingen and the countryside surrounding the river Aare have become popular places to stroll and relax in natural surroundings. This inevitably leads to a conflict of interest between nature and civilisation, with all too familiar consequences: litter, trampled shrubs and green areas, demolished fences, and startled wildlife. But given the necessary care and respect, this open reserve can be expected to continue developing well.

Environmental monitoring around the Ruppoldingen power station will continue over the coming years.

Aare-Tessin Ltd. for Electricity Corporate Communications