The Impact of River Engineering Works on the Dyje River floodplain in the Czech Republic

Abstract

Abstract The article deals with changes to the lower part of the Dyje River floodplain, Czech Republic, caused by river engineering works. It investigates channel changes as well as changes in the number of cut-off meanders (cut-offs), oxbow lakes (oxbows), and pools, focusing on the impact of river engineering works on land use and specific natural conditions of the floodplain. The author begins with a history of river engineering works in the study area and their impact from the perspective of natural conditions and human activities. She then divides the study area into five sections, according to the period when the works were carried out, and examines each one using graphical methods and old maps to determine their morphometric characteristics at different periods. Her research shows a significant shortening of the Dyje, a decrease in its sinuosity, and fluctuations in its surface area and in the number of cut-offs, oxbows, and pools. As regards the natural environment, the engineering works determined a lowering of the water table and some changes in plant species. From the perspective of human activities, in the form of land use changes, the study indicates that there was a significant reduction of meadow and pastureland, an increase in recreational areas, and a decrease in forestland during the period under investigation. Some of these changes – notably the increase of the overall water surface and the decrease of forestland – are a direct result of river engineering works, while others – the ploughing of the floodplain and the spread of recreational areas around reservoirs – are an indirect consequence thereof.