Reconstructed Runoff from the High Arctic Basin Bayelva based on Mass-Balance Measurements

Abstract

The river Bayelva drains a catchment area of 31.5 km2 in the Kongsfjord area close to the research station Ny-Ålesund (79° N 12°E) on the northwest coast of Spitsbergen. The basin is 54% glacierized, and the studied glacier Austre Brøggerbreen is 6.1 km2 and constitutes 20% of the basin. On this glacier a mass-balance monitoring program including accumulation and ablation measurements has been carried out continuously since 1967. The winter snow accumulation shows very stable conditions with a mean accumulation of 0.71 ± 0.16 m/year in water equivalent. The runoff from the glacier in an equilibrium year should thus be 4.33 × 106 m3. The mean ablation on this glacier has been greater than the winter accumulation, 1.14 ± 0.26 m/year of water equivalent, which results in an annual runoff of 6.95 × 106 m3. That is more than 60% higher runoff from the glacier than in a year with zero net balance. The result is a mean net balance of – 0.42 m/year, or an annual runoff from the glacier due to the retreat of the glacier of 2.6 × 106 m3. In Bayelva, a runoff station was operated from 1974-1978. In 1988 this basin was chosen as a hydrological research site, and the runoff measurements were restarted and a permanent station for water discharge and sediment transport measurements was constructed in the river. This basin is the only one in Svalbard with some years of hydrological data. The water balance discussion shows that there is good agreement between the measured runoff in the river Bayelva and the potential runoff calculated from the mass-balance measurements on Brøggerbreen. On the basis of this correlation the total annual runoff was reconstructed from the whole period of mass-balance data from 1967-1991. The runoff from the whole basin has been 30% higher than in years with an equilibrium mass-balance on the glacier.