Reduktion der pluvialen Überflutungsgefahr durch standortangepasste landwirtschaftliche Nutzung

Due to climate change, heavy rain events occur more frequently, causing damage in urban and rural areas through flooding. In order to reduce the risk for buildings and infrastructure, measures such as the areal retention of precipitation are necessary.
In Austria, around 32% of the total area is used for agriculture and can thus contribute significantly to runoff generation, but also to the reduction of pluvial flooding. Changing the type of soil tillage or crop can influence the infiltration rate and thus the extent of flooding as well as the groundwater recharge. However, there is still a need to quantify the possible reduction of surface runoff by agricultural measures.
In this study we use numerical rainfall-runoff modelling, based on physical soil parameters determined within a study area by laboratory and field investigations, to calculate the effects of two different agricultural uses (conventional corn field and regenerative grassland) on surface runoff for three different synthetic rainfall events (1-, 30- and 100-year return period).
The results show that in the study area, the runoff volume can be significantly reduced (up to 87%) through full-area cultivation as grassland instead of arable land, especially in the case of frequently recurring precipitation events.
Site-appropriate agricultural land use can thus potentially significantly reduce the risk potential for neighbouring settlement areas. Also, when planning technical flood protection measures, the inclusion of land use planning in the catchment area can be helpful in reducing the costs of these technical measures (e.g. by reducing the required retention volume).