Land use changes at the former “Iron curtain” and their implications for catchment hydrology, erosion and ecology – a transboundary project between Austria and Czech Republic

The river Maltsch / Malše is an interesting waterbody from a historical, hydrological and ecological perspective. As a border river between Austria and the Czech Republic, it has had an eventful history. With the political separation into “East” and “West” in the middle of the 20th century, a region that initially had a similar land use structure was completely changed. On the Czech side, villages and settlements were removed and the land expropriated. In the course of the fall of the Iron Curtain, the land was mostly sold to large landowners. Changes also took place on the Austrian side. Agriculture and forestry have been intensified over decades.

This leads to the situation that on both sides of the river, under very similar geological and hydrological conditions, the effects of very different land use developments and changes on the water household and erosion can be documented. Thus, a transboundary, mainly EU-funded INTERREG project was launched to investigate this variability in general and to address the implications for the sediment regime in such river systems (concerning e.g. flood protection control, sedimentation of reservoirs) in specific. Moreover, it is examined how mitigation measures for water retention, erosion control and climate change adaption can be planned under these variable boundary conditions. Especially droughts and heavy rainfall events must be considered as threats in the region in the future.

In addition to the changes described above, the political situation in the border region has left a refuge for nature. The Maltsch is part of the so-called Green Belt that stretches across the whole of Europe. A key species of the region is the Freshwater Pearl Mussel (Margaritifera margaritifera), which is characterised by its very high demands on the environment. It, therefore, serves very well as an indicator / umbrella species and thus also as a condensation nucleus of the different topics of the project.

In summary, the following aspects will be presented: (1) documentation of historic, political driven land use changes and land use differences on GIS basis, (2) effects on soil erosion by means of modelling via USLE, (3) estimation of the effects on the landscape hydrology and (4) effects on the aquatic fauna, especially the key species Freshwater Pearl Mussel.