Human impact on fluvial morphodynamics and contaminant dispersion in small river catchments (case study Wurm, Lower Rhine Embayment)

中欧的现代河流系统是人性化的河流系统。这种影响始于农业的开始，自中世纪以来（森林砍伐，磨坊池塘，密封）有所增加。此外，随着工业化的发展，水和沉积物的污染也在增加。此外，河流调控引起了河流形态动力学的显著变化。该项目侧重于人类对一个小集水区的影响。作为案例研究区域，我们选择了下莱茵河河口的Wurm河，其集水区面积为345平方公里。由于采煤传统悠久，部分河流采煤出现沉陷现象。这是由于矿廊坍塌造成地表和洪泛区的洼地。此外，工业废水和污水污染的水和沉积物。利用不同的方法（重金属、有机地球化学、铯137）可以检测河漫滩和洼地的沉积速率及其时空分布。来源特异性物质允许历史和空间分类以及点源、再活化和下游稀释效应的确定。开采沉陷和横向结构（如堰）对河流形态动力学的影响可以通过物理和数值模型来显示。这种涉及景观重建、地球化学和河流建模的跨学科方法的结果将显示人类对洪泛区河流动力学、空间分布和污染物再流动的直接和间接影响。从这个项目的成果转移到其他类似的河流系统显示了环境和社会问题的挑战。

Modern river systems in Central Europe are humanized fluvial systems. The influence started with the beginning of agriculture and increased since the medieval time (forest clearing, mill ponds, sealing). In addition, with the industrialization the contamination of water and sediment increased. Furthermore, the regulation of rivers induced significant changes in fluvial morphodynamics. This project focuses on human impact in a small catchment. As a case study area we chose the Wurm River in the Lower Rhine Embayment with a catchment size of 345 km². Due to a long tradition in coal mining in parts of the river mining subsidence occurred. This is a result of collapsed mine galleries, which causes depressions at the surface and in the floodplain. In addition, industry and wastewater sewage polluted water and sediments. The sedimentation rates in time and their spatial distribution in the floodplain and in the depressions can be detected by using different methods (heavy metals, organic geochemistry, Caesium 137). Source-specific substances allow a historic and spatial classification as well as the determination of point sources, remobilization and downstream dilution effects. The effects of mining subsidence and transverse structures (e.g. weirs) on the fluvial morphodynamics can be shown by using physical and numerical models. The results of this interdisciplinary approach involving landscape reconstruction, geochemistry and fluvial modelling will show the effects of direct and indirect human influence on fluvial dynamics and spatial distribution and remobilization of contaminants in floodplains. The transfer from results of this project on other comparable fluvial systems show challenges for environmental and social problems.