Alpine small hydropower: water ecology and the benefits for the region

The Saldurbach, a glacier-fed stream located in the Italian Central-Eastern Alps, is characterized by nivo-glacial hydrological dynamics. Fish are not present in the upper part of the catchment. In 2015, a run-of-river type hydropower plant (HPP) started its operation there. Concurrently with the project implementation, a study was launched to investigate the effect of the HPP on structure and function of aquatic macroinvertebrates (AMI) in different sites along the stream. This study could not detect an impact of the Saldur HPP on AMI, which were used as a proxy for detecting changes in the ecological structures and functions of the riverine environment. The structure of the AMI communities continued to show a clear trend of increase in dissimilarity and diversity with increasing distance from the glacial source, a commonly recorded pattern in glacier-fed streams worldwide, as in the Saldurbach itself when the HPP was not yet operating. Probable reason for this is that the regime of hydrology and sediments did not change after the HPP started operating. Even in the residual flow reach, the longitudinal connectivity of the stream was always guaranteed. In addition, HPP Saldur generates benefits for an alpine region during planning, construction, operation as well as maintenance and contributes to the improvement of the local infrastructure.