Over the last 200 years, most European river courses experienced significant irreversible changes. These changes were connected with different kinds of anthropogenic river use and exploitation, which varied from running water mills and rafting to large-scale hydroelectric power plants, industrial water withdrawal and measures for flood protection. Today, in most of the developed countries water quality and ecological river development are stakeholders in water management. The aim of the following study is to evaluate the specific impact of different time periods during the last 200 years on river courses, and its effects on the current river management using the example of the 165 km long German Rur River (North Rhine-Westphalia). The Rur River is a representative central European upland to lowland river, whose catchment has been affected by various phases of industrial development.
In this study, large-scale morphological changes over the last 200 years are determined based on historic maps and up-to-date orthophotos. The indicators river length, sinuosity, oxbow structures, sidearms and the number of islands are used to investigate human impact. The results are correlated with historic time periods.
This analysis shows that river straightening does increase especially during the industrial revolution, even without direct hydraulic channelization, which applies not only to the study area but also to further examples worldwide. The period and grade of river straightening has a direct morphodynamic impact on today’s river restorations. Since the Rur River is a typical upland to lowland river, the results show additional impact of geo-factors, like landform configurations.
The morphodynamic development is correlated with five historic periods between 1801 and 2019 of industrial development up to the introduction of the EU - Water Framework Directive (EU-WFD). Each period shows different influence on the watercourse which is connected with human intervention. Even if worldwide comparisons show that the five historical phases differ slightly in time between regions, they are applicable to other study areas.