Detection of Structural Changes in River Dynamics by Radar-Based Earth Observation Methods

Today, river dynamics is strongly influenced by human activities in the catchment affecting the hydrological behaviour, but also by activities in the floodplain. The knowledge in recent and historical river dynamics and the related morphological and structural changes in the Earth’s surface (e.g. sedimentation, accumulation, river bed movement) is one essential point regarding the flood risk estimation and the vulnerability of resources and structures. Operational Earth Observation (EO) systems provide data to monitor and to analyse both, the river dynamics and the small surface changes. Especially the radar-based systems and the interferometric data analysis approach are of high interest because of its potential in 3D information gathering. With selected sites at the river Odra area, we analysed the potential of radar-based EO-applications due to the detection of structural changes, validated by fieldwork. With the multitemporal approach we analysed the recent surface changes in the regions of interest, especially with view to the exceptional flood event in 1997. With the interferometric approach we were able to derive 3D information showing historical and recent river dynamics. Historical flood patterns but also retention areas were detected, important to modelling the behaviour of the river system. On the other hand, the integration of EO derived historical information in existing geo-databases is resulting in vulnerability maps showing high risk areas in the floodplain.