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. In this talk, the ongoing project, the water retention measures and the science that assesses the impact of nature-based water retention measures on increasing seasonal water availability and decreasing streamflow extremes will be presented.

Oliver S. Schilling^1,2

Co-authors: Paul Southard², Ruth Delzeit³, Johannes Heeb⁴, Lukas Kilcher^5,6, Sereina Grieder⁵

1 Tracer Hydrogeology, W+T, Eawag

2 Hydrogeology, Department of Environmental Sciences, University of Basel

3 Global and Regional Land-Use Change, Department of Environmental Sciences, University of Basel

4 Seecon International GmbH

5 Ebenrain, Kanton Basel-Landschaft

6 AGRIDEA