Comparative analysis of changes in hydromorphological conditions upstream and downstream hydropower plants on selected rivers in Poland and Belgium.

Currently, it is believed that the share of renewable energy in the overall balance of electricity production should increase in view of the climate change mitigation needs. Analysis of the current capacity of renewable energy shows that the hydropower constitutes the largest part. In this article, the authors undertook the assessment of the impact of hydropower plants on the hydromorphological conditions of the rivers on which they are located. Research sections located upstream and downstream of the facilities and on reference sections were investigated and compared for selected rivers in Poland (Oder, Bystrzyca, Ślęza Rivers) and Belgium (Meuse River). Impacts of the hydropower plants were studied based on 42 indicators, including physical conditions, coastal habitats, morphology, and hydrological regime. It was also determined which hydromorphological indicators influenced the hydromorphological conditions. Results show that in the sections upstream of the hydropower plants, the average hydromorphological state is moderate, whereas it is poor downstream of the plants and very good in the reference stations. From the 42 analyzed indicators, 26 show a deterioration in the hydromorphological state, and 14 show an improvement. The hydromorphological conditions are mostly influenced by anthropogenic pressures, the presence of transverse and longitudinal obstacles in the riverbed, river regulation, and changes in the hydrological regime and flow conditions. The presented methods used in individual EU countries (HIR, HEM, QBR, and MC) complement each other well and their results show a high convergence of the findings for the general hydromorphological state, with an average level of agreement of 82.14%. • Hydromorphological studies within hydropower plants in Poland and Belgium were shown. • Impacts of the hydropower plants were studied based on 42 indicators under 4 methods. • Hydropower plants have an ambiguous effect on the hydromorphology of rivers. • The most pronounced influence concerned the impacts on the hydrological regime. • There was a deterioration in 62.9% of the indicators, and an improvement – in 33.3%. [ABSTRACT FROM AUTHOR]