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.