Present-Day Changes in the Hydrologic Regime of the Raba River (Carpathians, Poland) as Inferred from Facies Pattern and Channel Geometry
- M. Marzo and
- C. Puigdefábregas
Published Online: 14 APR 2009
Copyright © 1993 The International Association of Sedimentologists
How to Cite
Wyżga, B. (1993) Present-Day Changes in the Hydrologic Regime of the Raba River (Carpathians, Poland) as Inferred from Facies Pattern and Channel Geometry, in Alluvial Sedimentation (eds M. Marzo and C. Puigdefábregas), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303995.ch21
- Published Online: 14 APR 2009
- Published Print: 16 SEP 1993
Print ISBN: 9780632035458
Online ISBN: 9781444303995
- changes in the hydrologic regime of Raba river;
- massive or crudely horizontally stratified pebble gravels;
- sands and gravelly sands showing large-scale trough cross-stratification;
- rise in mean annual flood and sediment delivery- high humidity;
- abating sediment supply and altered water run-off conditions;
- coarse debris facilitates erosion
Changes in the channel geometry and facies pattern of the Raba River, a mountain gravel-bed stream of the temperate zone, have been analysed to reconstruct transformations of the hydrologic regime during the last 200 years.
The river straightened, became shallower and widened during the nineteenth century. Point bar deposits showing a diversified facies pattern were then replaced with and overlain by very poorly sorted channel bar deposits of a low-sinuosity river. These changes are attributed to a marked increase in bed load due to the repeated occurrence of flash floods of high magnitude.
Channel degradation and coarsening of bed material during the twentieth century have resulted from increased stream power (channelization effect) and reduced sediment supply, due to variations in basin management and a change in flood hydrographs. A tendency to meander has reappeared but, as point bar deposits are much coarser now, the nineteenth century aggradational phase has had a persistent effect upon the river.