Glacier-dammed lake outburst events of Gornersee, Switzerland
2007 (English)In: Journal of Glaciology, ISSN 0022-1430, Vol. 53, no 181, 189-200 p.Article in journal (Refereed) Published
Gornersee is an ice marginal lake, which drains almost every year subglacially within a few days. We present an analysis of the lake outburst events between 1950 and 2005, as well as results of detailed field investigations related to the lake drainage in 2004 and 2005. The latter included measurements of lake geometry, water pressure in nearby boreholes, and glacier surface motion. A distributed temperature-index melt model coupled to a linear-reservoir runoff model is used to calculate hourly discharge from the catchment of Gornergletscher in order to distinguish between the melt-precipitation component and the outburst component of the discharge hydrograph. In this way, drainage volume and timing are determined. There is a clear trend since 1950 for the outburst flood to occur earlier in the melt season, though lacking any relation to lake discharge volumes. Peak discharges from the lake lie significantly below the values obtained with the empirical relation proposed by Clague and Mathews (1973). The shapes of the 2004 and 2005 lake outflow hydrographs differ substantially, thereby suggesting different drainage mechanisms. From water balance onsiderations we infer a leakage of the glacier-dammed lake starting one week prior to the lake outburst in 2005. During the drainage events up to 50% of lake water is temporarily stored in the glacial system causing substantial uplifts of the glacier surface.
Place, publisher, year, edition, pages
2007. Vol. 53, no 181, 189-200 p.
glacier, lake outburst, hydrology, melt modelling
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:uu:diva-20007DOI: 10.3189/172756507782202784ISI: 000248073500004OAI: oai:DiVA.org:uu-20007DiVA: diva2:47779