Glacier retreat and projected river regime changes in the hydrologically highly-coupled Virkisjökull catchment, SE Iceland

Abstract

Virkisjökull is an outlet glacier of the Öræfajökull icecap in SE Iceland and currently covers 60% of its catchment, though this is reducing. Fieldwork and catchment monitoring activities for this project over the last 4 years includes measurement of ice ablation, proglacial discharge, dye-tracing of flow pathways, and deployment of three automatic weather stations at altitudes up to 880 m. These data calibrate a distributed hydrological model (WaSIM) to project potential river regime during stages of glacier retreat. Results show: (1) glacier hypsometry sensitizes the catchment to a disproportionately rapid increase in runoff as the snowline rises resulting in a potential annual increase in river discharge of up to 37% ; (2) a dominantly channelized glacial drainage system in all seasons with a rapid runoff response to melt: englacial flow of 0.58 m s-1 is comparable to the proglacial river velocity; and (3) that longer-term, reduced glacier cover and snow storage will lead to a discharge regime dominated by short-term precipitation events in all seasons, and a reduced influence of the seasonal meltwater discharge peak. The study demonstrates the importance of glacier hypsometry above the present ELA as an influence on catchment hydrological response to potential climate warming. This study demonstrates the importance of considering changes at the catchment scale when discussing hydrological changes forced by enhanced glacier melt. Field work at Virkisjokull has revealled catchment-specific hydrological behaviour in the proglacial foreland that may have a large influence on the river regime as the glacier retreats.

Date of Award	2016
Original language	English
Awarding Institution	University of Dundee
Sponsors	Natural Environment Research Council & British Geological Survey
Supervisor	Martin Kirkbride (Supervisor), Andrew Black (Supervisor), Jez Everest (Supervisor) & Alan M. MacDonald (Supervisor)