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Home > Science and research > Geological hazards > Floods


The interaction of the changing climate, the expanding urban growth and the infrastructure development results in the increase of damage caused by heavy rainfall and ensuing inundations. The latter represents nature´s phenomenon brought about by sheet floods in a landscape outside the river beds and is accompanied by further geo-hazard processes such as bank erosion, lateral erosion and vertical erosion, corrosion and changing paths and lateral shift of river channels, avulsion and a swift material aggradation. This may cause varying amount of material damage, ecological damage or a number of human victims. The floods threaten particularly the households, the infrastructure and the corporate business bodies situated in the inundation areas. Investigation of the flood events and drafting of the damage remediation measures is an important part of the CGS´ research activities, particularly of the following subjects:

  • Detailed geomorphological analysis and investigation of the present-day or recent changes of river systems and their prediction in near future by using remote survey data (LIDAR, aerial photographs, multi-temporal satellite imagery), unmanned aerial vehicles (drones), ground radar, and geo-electric methods will be used for mapping the river bed dynamism. This involves the changes of river beds, and of flood plains, avulsion of river channels, meander pro-gradation, formation of channel-breaching fans and material aggradation.
  • The study of the depositional body of an alluvial plain and the closely related geological structures (river-bank stability, geological character of source area of the transported material) is a suitable tool enabling to predict the character of erosion or accumulation, and will be paralleled by using the archival core-library and geophysical data and accompanied by new geo-electrical methods.
  • Optimized approach towards dry-polder project in river valleys is based on utilizing the CGS data-sets – the borehole database, area-defined mapping units and modern methods of mapping and of inner structure study – LIDAR, unmanned aerial vehicles for photogram-survey, ground-penetrating radar (GPR) and geo-electrical methods for recognizing the inner structure of the alluvial plain.

Hanušovice after the 1997 inundation

Hanušovice below the confluence of Morava and Branná Rivers after the 1997 inundation. The from west- to- east shift of the Morava River course has brought about its straightenning along the east slope. Besides accumulating gravel in the original alluvial channel, the floods caused complete destruction of a football pitch and washed away the loam bottom after forming a gravel flat – a view from north. (Author: Jaroslav Aichler)

The objective of the research is to acquire key data for land-use planning and civil defense purposes, for preventing negative impact of geo-hazards and for remediation of damage caused by inundation hazards.

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Czech Geological Survey
Klárov 131/3
118 21 Praha 1
phone: +420257089570