RIBUST - Efficiency of riparian strips for the protection of water quality

• Project number: K3-F-130/005-2019
• Project management: Gabriele Weigelhofer, WasserCluster Lunz
• Project partner(s): Federal Office of Water Management / Institute of Cultural Engineering and Soil Water Management, Karl Landsteiner University for Health Sciences / Department of Water Quality and Health, University of Natural Resources and Applied Life Sciences, Vienna / Institute of Soil Research, Tulln
• Project duration: 48 months from 1 March 2020

Background

Almost half of the land in Lower Austria is used for agriculture. This leads to an increased surface input of phosphorus and nitrogen into the watercourses, which can be deposited in the sediments and lead to chronic eutrophication and oxygen depletion. In addition, stream sediments can serve as a breeding ground for introduced faecal pathogens. The problems are further aggravated by increased water temperatures and low water levels, which will increase in Lower Austria in the future due to climate change. Riparian strips and riparian forests represent measures that can protect flowing waters from the input of nutrients and pollutants from diffuse sources, improve their self-purification capacity and control the temperature and oxygen balance. In order to ensure their efficient and sustainable use and to be able to protect Lower Austrian watercourses also under future climatic conditions and agricultural use, detailed and interdisciplinary studies on the effects of these measures in different input situations are necessary.
The 4-year lead project deals with the potential of riparian strips and riparian forests to sustainably reduce the pollution of flowing waters by nutrients and microbiological faecal inputs under current and future climatic conditions. In the riparian zone, we use field experiments, soil analyses and a model to investigate under which conditions riparian strips ensure efficient phosphorus and nitrogen retention from area-wide sources. Using water and sediment samples from Lower Austrian streams along a land use gradient, we analyse how the presence or absence of riparian strips and riparian woody vegetation influences nutrient storage and release, oxygen consumption and the occurrence of faecal microorganisms in stream sediments. The results also form the basis for a risk assessment of future water quality deterioration due to climate change. Finally, we are using stable isotope analyses in controlled laboratory experiments to investigate whether or how organic material from riparian vegetation can positively influence the long-term binding of phosphorus and nitrogen from the water column. The use of state-of-the-art methods, the interdisciplinary combination of field studies with field and laboratory experiments and the expertise of the scientists involved ensure scientific findings at a high level. The lead project provides important information on the use of riparian strips and riparian woody plants for the management and protection of water bodies in agricultural catchments under current and future climatic conditions, which are of importance both for Lower Austria and internationally. The results should contribute, among other things, to being able to make necessary adaptations to global climate change in an optimal and forward-looking manner. The lead project links the expertise available in Lower Austria in the fields of water ecology (WasserCluster Lunz), soil water balance (BAW Petzenkirchen), soil research and stable isotope technology (BOKU Tulln) and water hygiene (KL Krems) and represents the first formation of a platform for holistic scientific expertise in the field of water and water bodies in Lower Austria with a lighthouse function in the Danube region. The project is anchored in the thematic fields of "Water", "Ecosystems and Ecosystem Services" and "Sustainable Land Management", and in the thematic field of "Water" includes the focal points of "Nutrient and Pollutant Transport", "Climate Change" and "Intelligent Indication Systems and Diagnostics".