Seasonal Variation of Solute Concentration in Melt Waters Draining from an Alpine Glacier

Abstract

Electrical conductivity of melt waters draining from the portal of Gornergletscher, Switzerland, was recorded continuously for extended periods during the 1978‐79 hydrological year. Conductivity was used as a surrogate measure of the total dissolved solids concentration in melt water to describe the seasonal variation of solute, and its relation to discharge, in an attempt to use melt-water hydrochemistry as an indicator of the nature of subglacial processes within an alpine glacier. In winter, conductivity was 2 to 10 times higher than during the summer ablation season. and also showed considerable diurnal and annual variations independent of discharge. The transition from winter to summer discharge regime was preceded by falling solute concentration. A distribution shaped as a “triangle-with-spike” describes the complex relationship between discharge and electrical conductivity for the annual cycle of run-off. Almost all the solute load from beneath Gornergletscher is evacuated during summer. Melt-water hydrochemistry provides some insight into the nature of sub-glacial chemical processes, but, since melt waters do not appear to have access to all areas of the glacier bed, it probably under-estimates total chemical activity.