The article presents the influence of precipitation sewage discharge on the hydrology and chemism of small streams. Catchment areas of small streams such as the Jamna river, the Mleczna river and Murckowski trench located within Upper- Silesian Industrial Area were chosen to be subjects of the research. It has been proved that precipitation sewage discharge to rivers contributes to dynamic changes of water chemism. They are the consequence of both the sewage quality itself and resuspention processes releasing polluted deposits into water. It is due to the downwash of salt used in winter to remove ice from roads. Erosional processes become more intensive as well leading to the transformation of cross-sections of river beds. In case of the Jamna river repeated increase in the area of the river bed cross-section in comparison with the period before intensive urbanisation of the catchment area took place. In case of a small stream – Murckowski trench (Katowice) the lowering of river bed bottom below the outlet of main precipitation sewage pipe reached 1.5m. ...
Dependly on the the land-use management, there are different technics of river training. The main aim of river training is floods mitigation. However, these activities often were done without any respect on the basic principle on keeping the ecological continuity of river corridor. In the current paper we present four types of trained river cross-sections, depend on their shapes, the material which forms them, and the condition for fauna and flora. There are also performed the patterns of the regulated channels, which are located in the different kind of urban area. For the selected trained river courses, which are located in the Upper Wisła catchment, the possibility of restoration has been analyzed.
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On Trzebuńka stream, in Stróża village, the project of lowering of 4.0 m and restoring the check dam has been executed. The structure downstream was redesigned to form rapids, made of stones embedded in the "grouted rock" construction. Now, the whole construction of 12 small water reservoirs forms a kind of long fish pass. The preliminary results of stream channel evolution on Trzebuńka stream above the restored check dam are presented in the paper. There are described the local cases of check dam liquidation or restoration in the World. However, there are still many questions concerning the response of stream channel to such technical intervention. The problem of rate of sediment displacement in the reservoir and the consequent erosion base reduction for the channel above is discussed. The field measurements and observation show that two years after check dam lowering and emptying the sediment reservoir on Trzebuńka stream the transformation of new formed channel upstream the new structure is dynamic. At the length of 180.0 m upstream the new dam the bank erosion is significant. Just above 200.0 m upstream from the structure the channel is stable. ...
A check dam is a hydraulic structure, which is constructed in order to limit river sediment transport. A sedimentation reservoir is created upstream from the body of the dam, where river sediment is constantlyaccumulated. These structures were constructed starting in the early 20th century in upstream parts of mountain streams in the Polish part of the Carpathian Mountains. At present, the reservoirs of most check dams are already fully filled with sediment and the impact of these structures on the ecosystems of streams is unfavorable. Moreover, the dams that have not been renovated are in poor technical condition. In the paper two cases of check dam lowering and restored is discussed and the one hypothetical case of gradual check dam lowering is presented and discussed as well. The cases of Krzczonówka and Trzebuńka, where the method ofremoving sediment from reservoirs was different, showed that the sudden change of „established" hydrodynamic conditions for decades is not favorable for the stream. The results of hypothetic simulation of gradual check dam lowering for the case of Isepnica Stream leads to the conclusion that lowering the construction of check dam and removing sediment from its reservoir in a way that does not have a ...
