ABSTRACT
Changes in the shape of the riverbed in longitudinal and cross-sectional profiles are natural processes, the course of which is affected by numerous factors, which include: hydraulic, hydrological, and geological conditions, as well as the development of riverbeds and the way they are exploited. Analyses of changes in the parameters of riverbed geometry and sediment diameters allow for determining the dynamics of processes taking place in rivers. The study was carried out in the section of the Warta River downstream of the Jeziorsko reservoir to the town of Uniejów and included the analyses of changes in sediment diameters in cross-sections over the period from 1995 to 2010. The phenomenon of sediment transport was analyzed with a computer program. Based on the known geometry of the bottom (data from 2009) and other parameters, the modeling of changes in the bottom over the course of one year was conducted. Then, the obtained results were compared with the measurements made in 2010. The most similar conditions to ones prevailing in the studied section were calculated using the MPM equation. On the basis of analyses carried out using the HEC-RAS model, the highest transport of sediment was observed at the end of May and the beginning of June 2010.
