River-Bed Morphology Changes During the Winter Season in the Regulated Channel of the Wilga River, Poland

Abstract

Field investigations of the river bed morphology in the regulated channel of the Wilga River in Poland are presented. All data were collected with the use of an echo sounding system mounted on the ADCP (acoustic Doppler current profiler), which was also used to obtain the water flow velocities, discharges and river bathymetry during the days of measurements. It is shown that the analysed channel consists mostly of regular sand waves, which change their length and height during the winter season. The dependence of the shape of bedforms and channel bed morphology on the existence of a vegetation patch, which is directly associated with decreasing water temperature, is discussed briefly. The paper confirms changes in bed profiles with the increase in the water discharge. Moreover, a 3-dimensional digital elevation model of the channel obtained with the use of the ArcGIS software is introduced. In addition, the single-sided spectra of bed-elevation are analyzed. The results suggest that in the case of vegetation existing in the channel, the spectra are characterized by a scaling region with the exponent “−2”, which tends to be “−3” when the plants disappear.