Historical and recent floods in the West Sudetes, Central Europe – the geomorphological dimension
Kasprzak, Marek; Migo, Piotr
published: Nov 1, 2015
ArtNo. ESP023105903004, Price: 29.00 €
The mountainous region of the West Sudetes in Central Europe is notorious for devastating floods generated by extreme precipitation. Localized cloudbursts are followed by floodings restricted to small headwater catchments, whereas longer periods of rain related to macroscale convergence result in regional-scale events. Multiple major floods can be identified in the historical records, which span the period from the 13th century. Severe floods occurred in the late 19th (1882, 1897) and early 20th centuries (1926, 1938), whilst the most recent events took place in 2006 and 2010. Consideration of spatial and temporal scales allows one to identify three types of floods: flash floods in small catchments (< 10 km 2), whose duration is limited to a few hours, short- and medium-duration floods (typically 1– 3 days) from topographically enhanced convergence, and long-duration floods, arising from persistent rainfall lasting for a few consecutive weeks. Geomorphic effects are most pronounced if daily precipitation exceeds 100 mm and/or hourly intensities are up to 50 – 60 mm. Flood-related landform change is particularly common in the piedmont zones, where widespread in-channel and overbank deposition takes place and new channels are cut. Distinctive patterns of erosion and deposition may be identified for different geomorphic settings, but they are all heavily influenced by the extent of anthropic modifications of channels and valley floors. Many mountain streams and rivers are lined with stone embankments and disconnected from original valley floors, which reduces the flood hazard under normal circumstances but exacerbates it under high and extremely high discharges.