Tracing Trends and Changes of Drought in Hydrosystems (TrenDHy)

• Applicant: Professorin Dr. Kerstin Stahl
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: from 2015 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 282339168

Drought has a wide range of impacts on environment, society and economy. The phenomenon and natural hazard of drought and its propagation through the environmental system requires more basic research. The overall objective of the project TrenDHy (Tracing Trends and Change of Drought in Hydrosystems) is the investigation and quantification of the resilience of coupled hydrological systems to meteorological drought. If a meteorological drought propagates into extreme low flows (also termed hydrological drought) it can have wide ranging direct impacts on river ecology, water supply, and navigation, as well as indirect damage potential for a range of economically important sectors. The central hypothesis is that global change will increase the risk of drought in headwater systems that supply water to a variety of downstream water uses as well. Specifically, the project will investigate long-term changes in two specific catchment systems that can sustain river flow during extended periods of meteorological drought: glaciers and groundwater. Methodologically, TrenHy will employ a regional approach and will combine statistical trend analysis of a large-n dataset of streamflow records for each system with the development of model-based attribution approaches for each system. The statistical analysis will investigate empirically the regionally characteristic, non-linear quantitative hydrological change trajectories for different hydrological systems with an emphasis on their response to dry periods (empirical change detection). The multi-modelling approach will first develop process-based models that can explain these changes through representation of the interacting direct and indirect changes that the hydro-climate has on the storage and release of water to streamflow during extended dry periods in different systems (model-based attribution). Finally, the models will be applied for the predictions of changes to the hydrological drought hazard based on the obtained understanding of system functioning, sensitivities and resilience (drought hazard scenarios). The approaches have a number of methodological challenges and require the developments of new methodology for the non-linear trend analysis, the transient model parameterization and application, and the scenario development and its use toward the characterization of a regional climate sensitivity of the studied headwater catchments. The results are expected to improve the understanding of the processes of a natural hazard that is expected to become more frequent and severe in the future in large parts of the world and therefore requires better risk assessment and management approaches.

• DFG Programme: Research Grants
• International Connection: Austria, Canada, Switzerland
• Cooperation Partners: Professor Dr. Gregor Laaha; Professor Dr. Dan Moore; Professor Dr. Jan Seibert; Professor Dr. Markus Weiler