Research

The main objectives of the project are: + to further develop and demonstrate the principle of retentive construction methods as elements of climate change adaptation in settlement areas, transport routes and for the prevention of pluvial floods (passive flood protection) + to gain insights for numerical simulations and to utilise these for the planning and operation of passive flood protection systems + optimising the use of synergies with carbon storage and biodiversity The central research topics are: + thesis: with the exception of high-ranking transport routes, retentive construction methods can be used everywhere where there is a need to adapt the components of the water balance (infiltration, evaporation and runoff) to local requirements (incl. groundwater management) + How can synergies in climate change adaptation of the water balance, carbon storage (in the soil) and conservation or reactivation of biodiversity be optimised with the use of nature-based methods (blue-green-brown infrastructure)? Description and evaluation of ecosystem services + nature-based retentive measures are to be developed, tested and modelled for the areas of windbreaks, viticulture, peri-urban settlements, housing estates, traffic route drainage and car parks + What influence do soil additives and/or soil organisms have on improving the properties of retentive construction methods, e.g. in terms of cleaning performance or plant vitality? The various elements of the technical substrates need to be analysed with regard to their effect on geotechnics, hydrology/hydraulics or filters and cleaning performance, especially by means of soil life and plants. + Scaling, dimensioning and test methods It is therefore necessary to develop dimensioning procedures, test parameters and test procedures for different construction methods to ensure their functions. These test procedures and parameters serve to ensure that they can be used in hydraulic construction methods in hydrological-hydraulic calculation and simulation procedures. Representative demonstration objects are used for the reliable validation of the water flows, which are to serve as the basis for simulation programmes in small and large areas. The data should be usable for open source or licensed modelling programs. + Integral modelling and monitoring

The project will attempt to answer the following questions from a scientific perspective: - How will meteorological variables such as temperature, humidity, wind speed and precipitation change under climate change conditions and how will their spatial and temporal patterns behave in Austria and at the other VERBUND sites in Europe? - How will the change in meteorological variables and their direct impact on hydrology (runoff, snow and glacier melt as well as extreme events such as floods and low water) change the conditions and potential for storage and run-of-river power in the future? What impact will changes in meteorological variables have on photovoltaics, wind energy and battery storage in Austria and other VERBUND AG sites? - How will climate change affect various meteorological, hydrological and geomorphological natural hazards (landslides, mudslides, avalanches, floods, tornadoes, droughts, etc.) on the site security of Austrian energy generation? - How will sediment deposits/bedload transport and water temperature change in the course of climate change? Will weir dimensions have to be adjusted? Is sufficient water availability guaranteed at the sites with hydrogen production?

Climate change increases the frequency and severity of droughts and rainfall events in Austria. The drought-related soil water deficit and the change in rainfall patterns poses a risk for forests, leading to increased tree mortality and loss of ecosystem services. The complex interplay of climate change impacts on trees and the associated response of hydrological components such as precipitation, soil moisture, or runoff is difficult to entangle under temporally-varying, natural conditions. However, detailed knowledge of forest and water interactions are urgently needed in promoting tree-resistance against climate change. Here, we propose controlled manipulation experiments using rain-out shelters and sprinklers to simulate drought and heavy rainfall events in a highly-instrumented, long-term measurement network located in a beech stand of the mountainous Rosalia forest (Lower Austria). We will quantify the percentage of summer and winter precipitation that beech trees transpire, and fluxes of evaporation, transpiration, and groundwater recharge using stable water isotopes. To achieve this, soil and xylem samples will be taken and analysed in the laboratory, and the results of this analysis compared to in-situ high-resolution measurements of soil water and xylem water isotopes using liquid-vapor equilibrium techniques. Further, we will quantify hydrological components using water balance methods and fluorescence tracers. This project will result in estimates of changes in water fluxes under climate change using controlled manipulation experiments as repeated experiments. We will gain insights into forest hydrological changes of Austrian, mountainous beech trees, from which suggestions for forest managers for strategies to promote beech health threatened by increased droughts and heavy rainfalls can be derived.