This summer we are interested in seeing how the glacier hydrology at Suldenferner connects to the sediment fluxes in the meltwater river exiting the glacier.
- Does meltwater discharge rate change over the summer?
- Does the changing discharge affect the sediment flux?
- If there are changes in the meltwater transfer efficiency does this mean changes in the drainage network, and how does that relate to the sediment discharge?
The Uni Innsbruck team is using dye tracing (with kind permission from Stelvio National Park), to investigate the hydrological part, while the Uni Bozen team monitors the sediment in the proglacial stream – both suspected sediment, and bedload. Its all part of the GLORI project which aims to understand how changing glaciers will affect river sedimentation in the coming decades.
At the end of June we were lucky enough to have Dr Cat Fyffe – a real expert in dye tracing on debris covered glaciers – join us. Here she is providing cheerful scale to a great basal ice exposure from which a meltwater stream emerges.
This area of the glacier is changing very rapidly this summer, and has retreated a lot over the last few years. The stream flow is very turbid, and at first we thought it must be a stream that flowed a longer distance at the bed of the glacier to pick up so much dirt, but our dye tracing experiments suggest that it is mostly a surface stream, that just happens to dip below the surface into this basal ice/medial moraine complex and picks up a lot of sediment just over the last tens of metres of its journey off the glacier.
Below is a gratuitous show of 50ml of liquid Rhodamine dye put in a few metres above a moulin in the centre of the glacier. Its shockingly bright initially, but invisible to the eye after a few hundred metres once it is diluted by the meltwater.