Effects of glacier retreat on the outbursts of Goësvatnet, southwest Spitsbergen, Svalbard
Abstract Effects of the retreat of Gåsbreen, southwest Spitsbergen, Svalbard, on the evolution of the ice-dammed lake Goësvatnet are shown for the period 1899-1991. The retreat and lowering of the damming ice masses have changed not only the stored lake volume, the lake geometry and the elevation, s...
| Published in: | Journal of Glaciology |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
1997
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/s0022143000003221 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000003221 |
| Summary: | Abstract Effects of the retreat of Gåsbreen, southwest Spitsbergen, Svalbard, on the evolution of the ice-dammed lake Goësvatnet are shown for the period 1899-1991. The retreat and lowering of the damming ice masses have changed not only the stored lake volume, the lake geometry and the elevation, slope and length of the subglacial outlet tunnel, but also the frequency and magnitude of outburst floods of Goësvatnet. For the estimation of peak discharges of outburst floods we computed an unbiased regression equation related to the progressive enlargement of subglacial tunnels using lake volume data and peak discharge data from the literature. The derived equation is very similar to the original form of the Clague-Mathews formula and answers the question why this formula has worked well in many cases. Peak discharges of Goësvatnet in various years were estimated by means of the derived equation. Effects of the changed lake geometry as well as the changed length and slope of the subglacial outlet tunnel on the discharge during outbursts will be discussed by means of the Nye-Clarke model. Observation of an outburst of Goësvatnet in summer 1991 indicates that the outbursts may have been triggered by pressure decrease in the subglacial outlet tunnel during increased discharge, whereas flotation of the ice dam can be excluded. |
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