Abstrakt

In light of the observed climate change, there is a need for better understanding of river ice processes for managing water resources in the cold regions. Ice jams produce significant resistance which may cause rise of water level and flooding. The jam resistance is only referred to the roughness of its underside, and this approach lead to exceptional roughness coefficients which has no physical explanation. Number of evidences and facts showed the analogy between the seepage flow in the ice jam and flow in open channel over rough, permeable bed. Base on the experiments where flow over rough, gravel bed was investigated it was concluded that the velocity over the bed is not zero, thus the seepage flow in the gravel exists. Taking all this into consideration, experiments conducted on ice jam model can help to develop theories on gravel bed, as well as during the study some theories from permeable bed can be adopted. This paper describes the first approach to gain preliminary understanding on the flow resistance of river ice jams. The study was carried out using the facilities at Gdansk University of Technology (GUT) where all hydraulic experiments were conducted. Experiments were proceed in hydraulic laboratory as a scale model of the real ice jam, because measurements in rivers are extremely dangerous and nearly impossible due to the risk of ice jam release during the surveying of the water velocity. Therefore scale model was set up to reproduce the typical condition observed in rivers. Since the facility on Gdansk University of Technology has no possibility to lower the room temperature to below freezing, the material similar to the ice was used instead (polypropylene, PP). Results shown that significant amount of water discharge formed the seepage flow through the jam voids.

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