Historical and present-day human impact on fluvial systems in the Old-Polish Industrial District (Poland)

Abstract The increase of intensive anthropopression since the Middle Ages has been recorded in numerous anthropogenic forms (embankments, dumps, canals, pits, etc.) and sediments (changes of sedimentation type, buried soils, slags, charcoals, geochemical changes) of the valleys of the Holy Cross Mountains. The development of small-scale water retention systems associated with functioning forges and mills on the watercourses resulted in changes in river patterns (anthropogenic anastomoses) and the reduction of the flood stage maximum during the Little Ice Age (on the Kamionka River). In the twentieth century, after the disappearance of the small-scale retention system caused by economic changes on the Kamionka and Czarna Konecka rivers, hydrotechnical failures appeared that led to the formation of catastrophic flash floods previously unknown during the Holocene. The geomorphological effects of these floods exceeded by many times the effects of secular processes.