Catriona Fyffe

PhD Thesis

The hydrology of debris-covered glaciers: implications for freshwater runoff under a changing climate.

Glaciers are a valuable source of freshwater, as they release water from storage when it is needed most. Importantly, many of the source areas of semi-arid regions contain debris-covered glaciers, with the number and extent of such glaciers increasing due to climate change. However, little work has been done on the particular effects a debris-cover may have on the internal hydrology, and consequent proglacial runoff from debris-covered glaciers. This project therefore attempts to gain an understanding of the functioning of the hydrological system of debris-covered glaciers, with an emphasis on the Miage Glacier, western Italian Alps. The structure and evolution of the drainage system will be investigated using a combination of dye tracing, water quality analysis and measurement of glacier velocity. The influence of debris on the surface stream network will be determined using mapping and the study of the characteristics of water flow through the debris layer. The water balance of the glacier is also likely to be effected, and this will be explored by measurement of evaporation from the debris, and of the fluctuations in water storage on surface lakes. Additionally, the improvement of the modelling of melt from a debris-covered glacier will be attempted using terrestrial photography. The finding of the above fieldwork will be analysed in the context of the proglacial stream discharge and detailed meteorological data, and will hopefully allow the construction of runoff models for debris-covered glaciers.