The IMPACT project is developing a model framework to disentangle and assess the effect of anthropogenic stressors on river biota (invertebrates and fish).

European streams and rivers have been altered by man throughout ancient and modern times, from deforestation, erosion and alluvial deposition in the Mesolithic Age to straightening, damming, water pollution, and increase in impervious cover in the 19th and 20th century. These human alterations led to a severe degradation of stream ecosystems.

Restoration of streams and rivers has become a widely accepted social objective in developed nations, which increasingly becomes established in law like in the European Water Framework Directive. Because this directive requires a good ecological status of all European rivers to be achieved by 2015, there is presently a strong demand for cost-effective restoration measures.

However, knowledge on the effect of restoration measures, which usually are applied at the reach-scale, is still incomplete. In particular, information on the limiting effect of the remaining anthropogenic pressures at larger scales are missing, including the effect of Climate Change.

The main objective of the IWRM-NET project IMPACT is to assess the relative importance of anthropogenic pressures operating at different spatial scales, to identify the main bottlenecks for river biota by coupling models, and to answer the following research questions:

  • What can you expect from local reach-scale restoration given the remaining pressures on larger spatial scales?
  • How important are discharge changes due to Climate Change compared to other anthropogenic pressures?
  • Will Climate Change have a major influence on natural reference conditions?

IMPACT is carried out with financial support from the Commission of the European Communities, specific RTD programme "IWRMNET". It does not necessarily reflects its views and in no way anticipates the Commission's future policy in this area. As an IWRM-NET project, funding is granted according to EU-member countries: German Federal Ministry of Education and Research (grant no. 02WM1134), French ONEMA (Office National de l'Eau et des Milieux Aquatiques), and Portuguese Foundation for Science and Technology / Fundação para a Ciência e Tecnologia.