Sand Island Reshaping in Response to Selected Discharges: The Vistula River Returning to Its Natural State
Andrzej Strużyński , Maciej Wyrębek , Adam Nowak , Agnieszka Woś , Jacek Florek , Leszek Książek
AbstractScientists have been researching processes leading to the formation of sand islands, but the process of their shaping when spate passes has not been accurately identified. Field measurements and numerical modelling of the Vistula river have been performed along a 1900 m section in which a sandy island with a nesting area for two species of tern exists. Numerical modelling covered a section with an island connected to the right bank of the river in 2017. As a result of observing changes in water levels and flows, two waves were selected and simplified to a uni-modal shape and run in the CCHE2D model. The following data were analysed: (i) survey measurements, discharge, and the flow velocity using an Acoustic Doppler Current Profiler; (ii) bars, islands, and water surface; (iii) the granulometric composition of bed material; and (iv) resources of the Head Office of Geodesy and Cartography in Poland (GUGiK). The purpose of the project is to determine limit discharges and related hydraulic parameters responsible for the growth or disappearance of a sand island. The limit discharge of the nesting is the moment when the whole island is submerged. The 2D modelling carried out provided data supporting the thesis that exceeding the conditions of bed material movement does not always lead to activating erosion processes. With the right load of material transported in the river bed, the transport capacity of the stream may be exhausted and, as a result, the bottom will not be eroded.
|Publication size in sheets||0.6|
|Book||Kalinowska Monika B., Mrokowska Magdalena M., Rowiński Paweł M. (eds.): Recent Trends in Environmental Hydraulics, GeoPlanet: Earth and Planetary Sciences, 2020, Springer, ISBN 978-3-030-37104-3, [978-3-030-37105-0], 318 p.|
|Keywords in English||Sand river, Island formation, Fluvial processes, 2D model|
|Publication indicators||: 2018 = 0.258|
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