Powodzie w dorzeczu Skawy w ostatnim dwudziestoleciu

Abstract

Four disastrous floods have occurred in the Skawa basin within the last twenty years: in June 1958, in July 1960, in July 1970, in August 1972. In his paper the author discusses morphological changes in the Skawa basin relief which are due to the floods, as well as evaluates economical damages resulting from these changes. He distinguishes morphological changes resulting in the bottoms of main valleys, in the bottoms of valleys which cross the Beskidy mountain-sides and finally changes over the slopes. The modelling of the bottoms of main valleys consisted primarily in a displacement of gravel heaps, in washing-out of the terrace steps, and in accumulation of terrace surfaces. Within the bottoms of mountain affluent valleys, a raise and an expansion of material due to side erosion took place. Modelling of valley slopes within the Skawa basin was restricted to rejuvenating of landslides and to slump formations in lower, undercut parts of the slopes. The total flood damage in the Skawa basin in 1958, 1960, 1970 and 1972 amounted to more than 564 millions zlotys. Erection of flood pools system in the Skawa basin is necessary, as well as a regulation and strengthening of river-beds.