Preliminary assesment of variability of Suspended load changes in cross-section Chalupki on Odra River

Abstract

Aim of the study: The aim of the study was to analyse the reasons for the occurrence of intensive suspended load transport in the area of meander 1. The river load transport caused significant morphological changes in the Upper Oder River bed system. Material and methods: For 16 years, the authors observed and studied the course of significant and quite intensive changes in the morphological system of the Upper Oder bed at the meandering section of the river in the vicinity of the Chałupki village. The course of these changes resulted in the creation of a new cut-off oxbow lake and shortening of the river course by about 1200 m. Trying to explain the course of these changes and the intensity of this process, the authors analysed hydrological data on the volume of suspended river load from 31 years (from 1969 to 2002). Results and conclusions: The analysis of changes in the intensity of suspended load transport in the flow function in the cross-section of Chałupki showed that the transport takes place virtually in the full range of flows specified in the hydrological characteristics for the analysed section and is mass. Maximum transport values can reach even 4000 g/m3. With an increase in average flows to about 250 m3 · s–1, the intensity of suspended load increases and at higher flows (Q > 250 m3 · s–1) the flow course is disturbed. At higher flow rates, smaller river load transport values occur. This would indicate (Morris and Fun, 1998) that the amount of river load eroded from the bottom of the river on a given section is possibly limited and associated with the presence of thick river load fractions (river bottom armouring or a rocky ground) below eroded sediments. This would confirmed by the earlier research of the authors on the mechanism of the course of morphological changes in the analysed section of the river (Głowski and Parzonka, 2008; Parzonka et al., 2006). Further research is needed to find out the exact causes of rapid morphological changes in the Oder River bed in the research area and to identify the mechanism of river load transport in this area.

Keywords

• sediment transport
• suspended load
• river morphology