Hydropower is considered a renewable energy source and its demand is considerably increasing in Europe. However, its global benefits are accompanied by significant environmental losses. Hydropeaking constitutes a major impact from hydropower dam operation. It refers to frequent changes in river flow occurring within the span of a day caused by turning the turbines on or off in response to varying demand in the energy market. As a result, downstream and upstream river hydrology, hydraulic parameters, water quality, river morphology, and ultimately the fluvial ecosystem, are modified. Despite the increasing environmental, social, industrial and regulatory requirements with regard to hydropower production and river ecological status in Europe (and worldwide), there is still much to learn about ecological processes affected by sub-daily flow changes along regulated rivers. Scientific studies are scarce and most of them focus on fish, leaving riparian vegetation uninvestigated. Hydropeaking may spoil the recruitment of riparian species and hence affect the maintenance of riparian populations. By analysing seed germination and seedling performance, it may be possible to reveal predictable relationships between hydropeaking and vegetation responses. Such relationships are crucial so as to objectively define thresholds which help to minimize the ecological effects of hydropower generation without causing significant production loss. The aim of this project is to investigate the opportunities for sustainable management of rivers subjected to hydropower production. To accomplish this goal, a thorough literature revision, analysis of sub-daily flow series, vegetation field-experiments and computer modelling are planned. The expected new contributions from the project are: (1) hydrological and ecological (i.e. riparian vegetation) metrics of hydropeaking impact, (2) hydrology-ecology models to quantify such effects and (3) measures for sustainable operation of hydropower dams.