Trash racks are the first element mounted in inlet channels of hydraulic structures. Their primary task is to capture coarse pollutants flowing in the riverbed/river channel and protect water facilities downstream. With the use of these devices, it is possible to separate coarse suspended matter, branches carried with the current, floating plastic elements, etc., which undoubtedly contributes to a trouble-free flow through culverts or channels and prevents hydroelectric power plant turbines from failure. An important issue here is also to ensure the proper operation of trash racks, particularly in respect of hydraulic structures whose task is to convert water energy into electricity (hydropower plants). Proper operation of trash racks minimizes losses arising from obstructing the free flow of water through accumulated waste or, in the wintertime, through icing. Incorrect work in this area entails specific head losses, and consequently leads to economic harm. In the paper, the resistance values of trash racks were analyzed at small hydropower plants (SHPs) operating at low temperatures, determined under laboratory conditions, with the occurrence of frazil ice and ice. The results indicate that the added ice into the channel resulted in the formation of a cover in front of the trash racks with an average thickness of about 0.02 m. The accumulated ice increased the head losses up to 14%. The range of the ice cover depended on the weight added ice and reached 0.6 m in analyzed cases.Energies 2020, 13, 1775 2 of 14 cover included only large watercourses, while information on smaller rivers was relatively scarce [8,9]. Winter river management is a key element of sustainable development regarding the use of water resources in cold regions [10].Buffin-Bélange et al. [11] noted that freezing processes occurring in smaller rivers are strongly dependent on their morphology, and because of their smaller size freezing actions are more contrasting and extreme. They result from a larger decrease in the water table and higher values of hydraulic forces characteristic for small watercourses. In addition, there is a risk that one watercourse can undergo several cycles of freezing processes, which can lead to aggregation of ice forms, with their varied shapes affected by the exchange process between ground and surface waters.Climate change is another important factor. However, it is pointed out that even if individual countries can feel the significant effects of climate change in connection with the production of hydropower, in global terms these changes should not lead to significant changes in hydropower generation [12]. Changes in ice and river regimes caused by climate change can have both positive and negative consequences for the operation of hydropower plants. The positive consequences are due to the shortening of icing time and the reduction of static ice loads. Negative consequences will be associated with unstable winters, which can lead to increased frequency of freezing and thawing in the winter season [13].Ice phenome...