Hydropower plants affect the distribution and composition of sediments. The main aim of this study was to analyze the spatial distribution of sediment pollution in the vicinity of a small hydropower plant. The grain composition of the sediments, the content of heavy metals (Cu, Ni, Cr, Zn, Pb, and Cd) and select physicochemical properties (pH, electrolytic conductivity) were tested at 14 points upstream and downstream of the hydropower plant on the Ślęza River in Poland, as well as at reference point. The interactions between the tested parameters were also verified. The results of the conducted analysis show that hydropower plants significantly affect the composition and properties of sediments. Large amounts of sediment are deposited on damming weirs, accumulating heavy metals and other substances. The differences in the concentrations of elements were significant, and Cu, Ni, Cr, Zn and Pb were 8.74, 9.53, 3.63, 8.26 and 6.33 times higher, respectively, than the median value at points upstream of the hydropower plant than downstream. It was shown that the tested parameters of the sediments interact with each other and are correlated; heavy metals showed a synergistic effect, while other parameters configurations showed an antagonistic effect. The higher content of heavy metals upstream of the hydropower plant resulted from the presence of finer sediment—classified as silt—in this section. Downstream of the hydropower plant, there were mainly sands, which showed a lower ability to absorb substances. This work contributes to improving the rational management of the worldwide issue of sediments within dams located in river valleys. Moreover, it is in line with the 2030 Sustainable Development Goals adopted by the United Nations, particularly in the fields of clean water and sanitation, clean and available energy, and responsible consumption and production.

Przedstawiono wyniki wstępnych badań jakości wody zbiornika Turawa przeprowadzonych w obrębie Instalacji Poprawiającej Jakość Wody w początkowym okresie jej funkcjonowania. Podano wyniki analizy zmian takich wskaźników wody, jak odczyn, przewodność elektrolityczna, azot azotanowy i fosfor fosforanowy. Analizy przeprowadzono z wykorzystaniem statystyk podstawowych i testu rang Wilcoxona. Na podstawie wyników uzyskanych w analizowanym okresie 2020 r. sformułowano wnioski dotyczące stopnia poprawy jakości wody poprzez obniżenie zawartości biogenów w wodach tego zbiornika. Wskazano możliwe kierunki rekultywacji zbiorników wodnych, które borykają się z eutrofizacją retencjonowanych w nich wód.

Floating debris (FD), encompassing both woody and anthropogenic materials, disrupts fishway hydraulics and ecological efficiency. Despite frequent usage in scientific literature, the term remains ambiguous. Motivated by the need to enhance fishway performance, this study examines the concept of FD. A substantial review of environmental, economic, and safety impacts was conducted, focusing on marine debris, microplastics, and woody debris. Additionally, a systematic analysis of 560 articles published from 2018 to 2023 assessed how FD is described across diverse contexts. Through an elimination process, 55 papers underwent detailed manual analysis. FD was categorized into natural floating debris (NFD) and anthropogenic floating debris (AFD), a distinction crucial for engineering and scientific applications. This classification supports fishway management by facilitating the identification and monitoring of debris accumulation, thus enabling strategies to mitigate hydraulic and ecological consequences. While FD poses risks such as habitat disruption and pollutant bioaccumulation, natural FD also provides potential ecological benefits, including habitat creation. To address these challenges, the study advocates innovative waste management strategies informed by concepts like the doughnut economy and ecological economics. These approaches aim to reconcile ecological sustainability with economic activities, reducing anthropogenic FD while leveraging the advantages of NFD.

Aim of the study: Cyanobacterial blooms lead to an increase in organic matter and higher concentrations of Biochemical Oxygen Demand over 5 days (BOD5) and Chemical Oxygen Demand (permanganate method) (CODMn), simultaneously causing oxygen depletion. In addition, pH levels rise, which may adversely affect the functioning of the aquatic ecosystem. The aim of this study was to evaluate the effectiveness of the Water Quality Improving Installation (WQII) in reducing (nitrate nitrogen) NO3-N concentrations and changing the organic matter content and pH of the water separated by a fin boom in reservoir. Material and methods: Generalized linear models (GLMs) were applied for NO3-N, BOD5, and CODMn and pH. Results and conclusions: The results showed a statistically significant decrease in NO3-N level at the tap outlet compared with the pipeline inlet. For the remaining parameters (pH, BOD₅, CODₘₙ), no statistically significant differences were observed, although a favorable downward trend in values was noted at the outlet of the installation. Measurements of NO3-N reduction efficiency showed markedly higher effectiveness in water collected directly from the installation tap (median 70%) compared to samples from the reservoir (median 39.4%), suggesting partial mixing of water within the reservoir. The reduction of NO3-N and organic matter limits the availability of nutrients for phytoplankton and reduces oxygen consumption, contributing to ecosystem stabilization and the improvement of the ecological quality of the studied reservoir. The results confirm the effectiveness of the applied installation in improving water quality parameters and reducing the risk of eutrophication.