Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
The erosionaland accumulation processes in floodplains after the flood of August 2002
Abstract
The flood of August 2002 possibly represents the biggest flooding event of the last 500 years. The culmination of Vltava north of Prague reached 758 cm, but lower part of Labe river witnessed a 1035-1230 cm rise of the water level. Overbank sedimentation was characterised by the basic types as follows: l.Pelitic sedimentation led to formation of surprisingly durable claystone crusts of 10-20 cm in thickness that evolved by slow iriented plane sedimentation of clay minerals; 2, sandy sedimentation lead to formation of sheet deposits, aggradation rims and sand dunes, sometimes up to 2 m high; 3, gravel accumulated as bars and benches (see photo documentation). The erosional processes were surprisingly variable. Due to the changing morphology weak sandy sedimentation could change within few meters into boulder field where individual blocks up to 80 cm in diameter could be transported. Parallel river channels developed at some places behind aggradation rims.
