Links between glacial meltwater and proglacial groundwater upwellings at Scott Turnerbreen, Svalbard.

Abstract

Proglacial water upwellings and their winter icings have long been seen as indicators for the presence of polythermal glaciers. However, these features have been observed in front of cold based glaciers as well. This means understanding of drainage system behaviour in cold-based glaciers and their fore fields on Svalbard does not conform to the current expectations. This thesis therefore presents a field based study on the links between glacial meltwater and proglacial water upwellings at Scott Turnerbreen, a cold based high arctic glacier. The summer meltwater production and runoff at Scott Turnerbreen is characterized by monitoring the bulk discharge and two proglacial water upwellings during summer 2020. The hydrograph analysis and numerical modelling reveals a system with two linear stores including a clear baseflow component that sustains river flow at least until early October. Thereafter, outflow continues but freezing temperatures result in icing formation. Pathways taken by runoff in the Scott Turnerbreen catchment with a particular emphasis upon groundwater are identified by analysing samples and measurements taken from the glacier ice, glacial meltwater and the proglacial water upwellings. The samples taken at the different sites in the Scott Turnerbreen catchment are all predominantly sourced by winter precipitation, and therefore broadly follow the Global Meteoric Water Line with a similar stable isotopic composition. The samples from the Scott Turnerbreen sites are different to water samples from sub-permafrost groundwater in Adventdalen. All measured water flows in the Scott Turnerbreen catchment therefore have a local glacial source. These results lead to a conceptual model that explains the links and provenance of the proglacial water upwellings and discharge at Scott Turnerbreen by intra-permafrost groundwater flow. Further investigations in the possibility of similar processes at other cold based glaciers in Nordensköldland is recommended to test the purposed conceptual model.