Bathymetric Monitoring of Alluvial River Bottom Changes for Purposes of Stability of Water Power Plant Structure with a New Methodology for River Bottom Hazard Mapping (Wloclawek, Poland)

Dariusz Popielarczyk; Marian Marschalko; Tomasz Templin; Dominik Niemiec; Isik Yilmaz; Barbara Matuszková

doi:10.3390/s20175004

Bathymetric Monitoring of Alluvial River Bottom Changes for Purposes of Stability of Water Power Plant Structure with a New Methodology for River Bottom Hazard Mapping (Wloclawek, Poland)

Sensors (Basel). 2020 Sep 3;20(17):5004. doi: 10.3390/s20175004.

Authors

Dariusz Popielarczyk¹, Marian Marschalko², Tomasz Templin¹, Dominik Niemiec², Isik Yilmaz³, Barbara Matuszková²

Affiliations

¹ Department of Geodesy, Faculty of Geoengineering, University of Warmia and Mazury, Heweliusza 5, 10-724 Olsztyn, Poland.
² Department of Geological Engineering, Faculty of Mining and Geology, VŠB-Technical University of Ostrava, 17 listopadu 15, 708 33 Ostrava, Czech Republic.
³ Department of Geological Engineering, Faculty of Engineering, Cumhuriyet University, Sivas 58140, Turkey.

Abstract

The aim of this research was to produce a new methodology for a special river bottom hazard mapping for the stability purposes of the biggest Polish water power plant: Włocławek. During the operation period of the water power plant, an engineering-geological issue in the form of pothole formation on the Wisła River bed in the gravel-sand alluvium was observed. This was caused by increased fluvial erosion resulting from a reduced water level behind the power plant, along with frequent changes in the water flow rates and water levels caused by the varying technological and economic operation needs of the power plant. Data for the research were obtained by way of a 4-year geodetic/bathymetric monitoring of the river bed implemented using integrated GNSS (Global Navigation Satellite System), RTS (Robotized Total Station) and SBES (Single Beam Echo Sounder) methods. The result is a customized river bottom hazard map which takes into account a high, medium, and low risk levels of the potholes for the water power plant structure. This map was used to redevelop the river bed by filling. The findings show that high hazard is related to 5% of potholes (capacity of 4308 m³), medium with 38% of potholes (capacity of 36,455 m³), and low hazard with 57% of potholes (capacity of 54,396 m³). Since the construction of the dam, changes due to erosion identified by the monitoring have concerned approximately 405,252 m³ of the bottom, which corresponds to 130 Olympic-size pools. This implies enormous changes, while a possible solution could be the construction of additional cascades on the Wisła River.

Keywords: GNSS/SBES measurements; Poland; Wisła River; alluvial river bottom changes; bathymetric monitoring; river bottom hazard mapping; stability; water power plant structure.