Hydropeaking causes one of the most important environmental impacts on running water ecosystems in Austria. About 800 km of rivers (mainly in the grayling zone) are affected by hydro peaking due to hydropower production. These rivers have experienced severe flow alterations due to human activities and are characterized by dynamic perturbations in their hydrographs. Habitats for fish and invertebrates can be reduced, abundances can be diminished and organisms are affected by drift and stranding during the increase and decrease phase of peaks. To assess the ecological impact of hydro peaking, intensity thresholds according to different species and life stages can be applied. However, due to retention effects the hydrological impact is not constant in a longitudinal view. A model to assess hydro peaking impacts considering distances to the power plant outlets is needed. According to this, we developed a model by detecting fluctuation intensities out of multiple hydrographs along the affected river reaches. That allows to describe potential effects of hydro peaking in detail by contrasting the varying hydro peaking intensity to threshold values of river organisms. Furthermore, mitigation scenarios can be evaluated both, ecologically and economically, by modelling modified hydro peaking intensities.