Prof. Dr. Oliver Schilling

English:

Mountainous countries like Switzerland are overproportionally affected by climate change, with temperature rise and increasing weather extremes such as heat waves, droughts, and torrential rainfalls already being more pronounced than elsewhere. Under these circumstances, water supply is becoming a major challenge for agriculture, be it for crop production or animal husbandry. In addition, water in mountain communities becomes increasingly scarce during summer months. This is where the Swiss Federal Office of Agriculture FOAG-funded "Slow Water" project comes in: In 3 hydrologically and geographically distinct pilot regions of Switzerland, farm-specific, catchment-related water retention strategies are developed and implemented based on a catalogue of 15+ different nature-based water retention measures, through a co-creation process involving municipalities, farmers, authorities and scientists. The integral impacts of the nature-based water retention measures on increasing water availability and decreasing streamflow extremes are assessed through a combination of hydrological monitoring, drone-based assessments and numerical modelling. The Slow Water project consortium consists of the Hydrogeology and the Global and Regional Land-Use Change groups of University of Basel/Eawag, the regional authorities of the Cantons of Basel-Landschaft and Luzern, municipalities, farming associations and the private sector.

Deutsch:

Alpenländer wie die Schweiz sind überproportional vom Klimawandel betroffen, und der Temperaturanstieg und zunehmende Wetterextreme wie Hitzewellen, Dürren und Starkregenereignisse sind hier bereits jetzt ausgeprägter als anderswo. Unter diesen Umständen wird die Wasserversorgung zu einer grossen Herausforderung, insbesondere auch für die Landwirtschaft, sei es für den Pflanzenbau oder die Tierhaltung. Darüber hinaus wird Wasser in Gemeinden ohne Anschluss an grössere Grundwasservorkommen, Flüsse oder Seen, was typisch ist für Berggemeinden, während der Sommermonate zunehmend knapp. Hier setzt das vom Bundesamt für Landwirtschaft BLW finanzierte Ressourcenprojekt «Slow Water» an: In drei hydrologisch und geografisch unterschiedlichen Pilotregionen der Schweiz werden auf der Grundlage eines Katalogs von mehr als 15 verschiedenen kleinskaligen, naturbasierten Wasserrückhaltemassnahmen in einem ko-kreativen Prozess unter Einbezug von Gemeinden, LandwirtInnen, Behörden und WissenschaftlerInnen betriebs- und einzugsgebietsspezifische Wasserrückhaltestrategien entwickelt und Massnahmen umgesetzt. Die integralen Auswirkungen der naturbasierten Wasserrückhaltemassnahmen auf die Erhöhung der Wasserverfügbarkeit und die Verringerung von Extremabflüssen werden durch eine Kombination aus hydrologischer Überwachung, drohnenbasierten Analysen und numerischer Modellierung bewertet. Das Konsortium des «Slow Water»-Projekts besteht aus den beiden Forschungsgruppen Hydrogeologie und Globale und regionale Landnutzungsänderungen der Universität Basel und der Eawag, den regionalen Behörden der Kantone Basel-Landschaft, Basel-Stadt und Luzern, Gemeinden, Landwirtschaftsverbänden und dem privaten Sektor.

Humanity has reached a point where the capacity to live without irreversibly compromising Earth’s resources is questioned. Since the 1980s, both Earth’s population and global food production have been constantly increasing. To face the challenges of increasing food and water demand, agricultural production efficiency must be improved. Initiatives like the UN Sustainable Development Goals (SDGs) describe major challenges for clean water and food production. Accordingly, food production and access to clean water must be a priority in the context of sustainable development. To tackle these important challenges to sustainable development, the present project will build on a combination of agricultural field and integrated hydrological modelling experiments. The knowledge obtained in the field and modelling experiments will be ultimately combined to enable the creation of a prototype near-real time decision support tool for sustainable and resilient management of nitrogen fertilization.

In Poland, cereal production is a major component of the national economy. Even though fertilizer use has been restricted since 2017, in 2020 the Polish government still reported a significant trend of increasing nitrogen concentrations in water bodies. Climate change makes agricultural production even more vulnerable and challenging, pushing farmers to overfertilization. Given the fact that 30% of Polish agricultural soils consist of soils highly prone to fertilizer leaching, it comes as no surprise that excessive nutrient loadings are still widely observed. Due to its high mobility, the most applied agricultural fertilizer Nitrogen (N) is the most prone to leaching, and as a result, N (primarily in the form of nitrate) is by far the most widely observed agricultural contaminant in water bodies worldwide, including in Poland and Switzerland.

To tackle these important challenges to sustainable development, the project will build on a combination of field and modelling experiments. The Swiss project partner will focus on the integrated simulation of hydrological fluxes, crop dynamics and nitrogen-cycling. The Polish project partner will focus its research on field experiments in agricultural fields and in the university's outdoor agricultural laboratory. The knowledge obtained in the field and modelling experiments will be ultimately combined to enable the creation of a prototype near-real time decision support tool for sustainable and resilient management of nitrogen fertilization.

The broad focus of this research project is the improvement of the conceptual and quantitative understanding of surface water-groundwater interactions via state-of-the-art tritium measurement techniques and integrated surface-subsurface hydrological modelling. The specific goal is the development of a dissolved gases and water stable and tritium isotopes based method for the continuous monitoring of managed aquifer recharge (MAR) systems, which are considered the most important mitigation measures against the negative impacts of climate change on water availability. The field site is Switzerland's largest managed aquifer recharge (MAR) site Hardwald in Muttenz, Basel. Continuous analysis of the spatial and temporal distribution of tritium in the river Rhine and in the groundwater wellfield is achieved with the deployment of portable mass spectrometers for dissolved gas analyses and automated sampling devices for the sampling for water for isotopic analyses. In addition, within the framework of the project a new state-of-the-art tritium enrichment line is being built within Eawag's environmental tracer laboratory. The new enrichment line is combining recent methodological developments of IAEA's isotope hydrology laboratory and of Eawag's environmental isotope tracer group. The measurement of low-level tritium concentrations will thus be made possible via an improved electrolytic enrichment method for tritium in small volume water samples, followed by low level liquid scintillation counting. The efficient measurement system for natural to ultra low level tritium concentrations, the online monitoring of dissolved gases and the integrated modelling method will provide a new toolbox for the near real-time quantification of the flow and mixing of different groundwater sources in MAR systems. The numerical modelling is based on a high resolution 3-D geological model incorporated into an integrated surface-subsurface hydrological model (ISSHM). The modelling software HydroGeoSphere, the inverse modelling software PEST++ and the data assimilation software PDAF will be used for model construction, model calibration and real time modelling.