The destruction of natural river reaches due to improper land development - an example of the valleys of Czadeczka and Krężelka rivers (Beskid Śląski Mts) / Niszczenie naturalnych odcinków koryt rzecznych na skutek niewłaściwej zabudowy – przykład dolin Czadeczki i Krężelki (Beskid Śląski)

Channels of Czadeczka and Krężelka rivers (Beskidzie Śląski Mts) are at present subjected to regulation because of which these rivers have lost their natural character, partially still preserved. The reasons for the river regulation have been analysed. Using archival maps, the buildings erection time has been analysed on valley floors, in the immediate vicinity of river channels for the period 1790-2012. Next, the distribution of existing buildings has been compared with hydraulic structures in the channels developed in order to regulate the Czadeczka and the Krężelka reaches, such as: concrete and stone embankments reinforcing the channel banks, check dams on channel bottoms. Results indicate a strong correlation between the number of buildings on valley floors in the 20^th century and channel regulation. The mechanism of destroying rare, preserved natural river reaches is based on irrational permission allowing construction of buildings in areas threatened by floods and lateral erosion of rivers. Consequently, the inhabitants, in fear of floods and erosion of land or house foundations, seek river regulation that gives them a false sense of security. Natural river reaches are destroyed though efficient protection against floods and lateral erosion is still not provided and the range of possible losses increases even more due to continued building erection.