Hajdukiewicz Hanna, Hajdukiewicz Maciej, Ruiz-Villanueva Virginia, Radecki-Pawlik Artur, Zawiejska Joanna
Institute of Nature Conservation, Polish Academy of Sciences, al. Mickiewicza 33, 31-120 Kraków, Poland.
Department of Environmental Engineering, Geomatics and Energetics, Kielce University of Technology, al.Tysiąclecia Państwa Polskiego 7, 25-314 Kielce, Poland.
Sci Total Environ. 2024 Oct 20;948:174742. doi: 10.1016/j.scitotenv.2024.174742. Epub 2024 Jul 14.
During the 20th-century many mountain rivers in Europe were subjected to intensive human impacts which substantially modified their channel morphology. How these changes affected river hydrodynamics and response to floods remains uncertain. In this work, we perform hydraulic modelling using data from archival aerial photos to explore relations between hydraulic parameters of floods and human-induced channel incision occurring on the Czarny Dunajec River (Polish Carpathians) between 1964 and 2012. Data on vertical position of the channel used for two-dimensional modelling of flood flows were extracted (as Digital Elevation Models DEMs) from archival aerial photos from 1964 and 1983 and ALS (Airborne Laser Skanning)-derived DEM from 2012. Water depth, flow velocity, bed shear stress, and sediment critical diameter were modelled for four flood scenarios (2-year, 5-year, 20-year, and 50-year floods) as well as the extent of flooded area and additionally the grain size of channel sediment was calculated. The values of water depth, flow velocity, bed shear stress and sediment critical diameter increased significantly between 1964 and 1983, especially for 20-year and 50-year floods. Only the flow velocity within the floodplain zone did not increase for the two largest flood scenarios due to the expansion of riparian forest in the second half of the twentieth century. The increase in flow rate was accompanied by a progressive reduction of the extent of flooded area, especially between 1964 and 1983, as well as by increase in mean grain size of channel sediment. Between 1983 and 2012 changes in hydraulic parameters were less pronounced, and coarser and well packed channel sediment dominated on the river bed. Our work demonstrates that reconstruction of past river hydrodynamics, rather than river state at time horizons, can give essential insights into functioning of the river channel and floodplain during the intensification of human impacts after 1950s.
在20世纪，欧洲的许多山区河流受到了强烈的人类影响，这极大地改变了它们的河道形态。这些变化如何影响河流水动力以及对洪水的响应仍不确定。在这项工作中，我们利用档案航空照片的数据进行水力建模，以探讨1964年至2012年期间，在恰尔内-杜纳耶茨河（波兰喀尔巴阡山脉）发生的洪水水力参数与人为导致的河道下切之间的关系。用于洪水水流二维建模的河道垂直位置数据（作为数字高程模型DEMs）是从1964年和1983年的档案航空照片以及2012年机载激光扫描（ALS）得出的DEM中提取的。针对四种洪水情景（2年一遇、5年一遇、20年一遇和50年一遇洪水）对水深、流速、床面剪应力和沉积物临界直径进行了建模，同时还计算了淹没面积范围，另外还计算了河道沉积物的粒度。1964年至1983年期间，水深、流速、床面剪应力和沉积物临界直径的值显著增加，特别是对于20年一遇和50年一遇的洪水。由于20世纪下半叶河岸森林的扩张，在两种最大洪水情景下，只有洪泛区的流速没有增加。流量的增加伴随着淹没面积范围的逐渐减小，特别是在1964年至19年期间，以及河道沉积物平均粒度的增加。1983年至2012年期间，水力参数的变化不太明显，河床以更粗且堆积良好的河道沉积物为主。我们的研究表明，重建过去的河流水动力，而不是时间范围内的河流状态，能够为20世纪50年代后人类影响加剧期间河道和洪泛区的功能提供重要见解。
