Sedimentation of load in a step-pool rock ramp fishway with biotechnical embedded elements

such structures has resulted in a more and more conventional approach to their design. However, every single hydraulic engineering structure with a negative impact on the possibility of a watercourse in fact requires an individual approach. Often, the solutions which are the most convenient and the easiest for a designer are not in the least the best ones for migratory fish. Semi-natural fishways in particular pose a technical challenge that requires an interdisciplinary approach. Designing and constructing them correctly is not an easy task, but once it is achieved, the structure is highly effective in terms of fish migration and the formation of new habitats. Another, equally important issue related to fishways of this type is their long-term usage and proper maintenance. In this case, it is crucial to consider the transport of load through the fishway channel, and more particularly its sedimentation in zones of lower flow velocities. This paper presents a qualitative analysis of the sedimentation of load based on laboratory research carried out on a model of a vegetated fishway. This research was performed to investigate and confirm the expected locations of accumulation of load in a semi-natural vegetated step-pool rock ramp fishway. Experiments show that the sedimentation of load in fish passes may be a highly problematic issue and may require that more attention be given to the proper upkeep of fishways. It may be necessary to address the problem of fishway maintenance and deal with fishways as structures that change over time not only because of hydrological conditions, but also due to the yearly growth cycle of vegetation.