Sedimentary-vegetation response to the channel by-pass: A case study of the Danube river

The Gabčíkovo-Nagymaros waterworks construction on Danube river in Slovakia (1977−1992) was followed with major ecological consequences. The water level and flow velocity was decreased in the original by-passed channel in order to keep high water level for shipping in the bypass canal. The decrease in discharge and lowering flow velocity resulted in the channel narrowing and increase in the vertical accretion magnitude in new floodplain pockets along both sides of by-passed channel. What is more, anthropic intervention in form of groynes structures built for channel adjustment before 1992 dramatically accelerated this process. Vegetation colonisation took place on the new floodplain. In this paper, we analysed land cover changes - vegetation succession using aerial photographs taken in 1986, 1996, 2004 and 2013 as well as field surveys. After the flood in 2013, the area of the new floodplain reached 57% (310 ha) of the original channel area.