Summary:

The analysis of variability of riverbed elevation recorded at three selected gauging cross-sections: Stróża on Raba River and Żywiec and Oświęcin on Soła River is presented in the current paper. The studies concern the period of more than one hundred year. Focus was on the analysis of the river course maintenance in selected gauging stations. Research shows that the river course may change spacially and temporally with varying inensity. In the period of 50 - 100 years, these changes can be slight, but it can be also observed permanent change in the direction of the river channel development. The paper presents the trends of riverbed changes during the long period of time in selected mountain tributaries of the upper Vistula River, which were studied on the basis on the variability of observed mean annual water stages. In the paper there are given the reasons for the observed changes in the river course and channel geometry, which were caused by river regulation relayed on the shortening and narrowing of the river channel or the sediment exploitation. Presented in the article method of assessment of the variability of the river channels level in the long period of time may be the first step to future research on trends in the river channel and rivel valleys development