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，自中世纪以来不断增加(森林砍伐、磨坊池塘、封地)。此外，随着工业化进程的加快，水体和底泥的污染也越来越严重。此外，河流的整治引起了河流地貌动力学的显著变化。这个项目的重点是人类对一个小流域的影响。作为案例研究区域，我们选择了位于莱茵河下游海湾的乌尔姆河，流域规模为345平方公里。由于煤炭开采传统悠久，部分河流发生了开采沉陷。这是矿坑坍塌的结果，导致地面和泛滥平原的凹陷。此外，工业和废水污水污染了水和沉积物。用不同的方法(重金属、有机地球化学、铯137)可以检测滩地和洼地沉积速率的时间和空间分布。特定来源的物质允许对历史和空间进行分类，以及确定点源、再动员和下游稀释影响。开采沉陷和横向构造(如堰)对河流地貌动力学的影响可以通过物理模型和数值模型来显示。这一涉及景观重建、地球化学和河流模型的跨学科方法的结果将显示直接和间接的人类影响对河流动力学和洪泛区污染物的空间分布和再动员的影响。将这一项目成果转化为其他可比河流系统的成果，显示出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.