COnnecting GLAcier Changes with mountain Streamflow globally – CoGlaCS

• Applicant: Dr. Marit van Tiel
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 510684314

Dwindling glaciers all around the world have become one of the most dramatic evidences of global climate warming. This loss of ice affects our mountain water resources. The global warming effect on glacier meltwater supply has been conceptualized as a non-linear response. A warming climate will first cause more melt and thus increasing streamflow over time. This is followed by a decreasing streamflow trend because the reduced glacier volume due to extensive melt, will provide less melt contribution to the rivers. This changing point, from increasing to decreasing streamflow trends, is called glacier peak water. When this so-called peak water moment will occur is currently a hot topic in glacio-hydrological research. However, this glacier-water resources question has mostly been approached from different disciplines, glaciology and hydrology, without fully bridging and integrating these fields. This has resulted in glaciological simulations of changing melt water supply, without considering how this meltwater flows further downstream, and hydrological simulations of streamflow without fully considering the dynamics of individual glaciers within catchments. Little is known how and at which scales retreating glaciers affect downstream streamflow and it has been difficult to detect peak water in streamflow observations. Moreover, due to limited observations at high elevations, only few catchments around the world have been analyzed, thus lacking knowledge on glacier change impact on water supply at the mountain range scale and beyond. Therefore, this research project, called Connecting GLAcier Changes with mountain Streamflow globally (CoGlaCS), aims to advance our understanding of past and future changes in mountain water supply at regional to global scales by integrating glaciological and hydrological knowledge, observations and approaches, to improve water management in a changing climate. In the CoGlaCS project, streamflow observations and glacier changes of mountain catchments around the world will be brought together in a large sample catchment dataset to analyze the effect of glacier retreat on water supply. Consequently, using a water balance approach, the role of groundwater in these glacierized mountain catchments will be examined. These analyses will then be extrapolated to the mountain range scale by developing and applying a glacio-hydrological model framework that combines the global glaciological model GloGEM and the alpine hydrological model HBV. Past and future changes in glacier melt water supply and streamflow will be modelled to quantify the changing water availability from our mountain water towers and to investigate drivers and controls of streamflow and glacier melt changes.

• DFG Programme: WBP Fellowship
• International Connection: Switzerland
• Hosts: Professor Dr. Daniel Farinotti; Professorin Dr. Bettina Schaefli