Past and recent evolution ot the Jelení potok floodplain (Opava catchment, Czech Republic)

Abstract

Floods are considered to be a crucial agent influencing the formation of the floodplain. The knowledge of the floodplain evolution can be therefore an important source of information about the past floods magnitude and frequency. Recent and past dynamics of the Jelení potok floodplain (Opava catchment) was analyzed in this study using dendrochronological and geomorphological methods. Complex structure of the floodplain was usually represented by gravels covered by distinct layer of line-grained sediment. The beginning of the floodplain development by accumulation of finegrained particles is estimated to be of the Medieval age (ca 900 years BP). Up to 60 cm of barny silts have been deposited since that period. Lateral erosion of the channel is recently a dominant geomorphological process in the studied floodplain. The most extensive erosional landforms (bank scours, Hood channels) were formed during the July 1997 Hood. In addition, another two Hood events were recorded based on dendrochronological markers. Recent dynamics ofthe Jelení potok floodplain is, however, strongly affected by human- induced transformation of the channel