Discharge, water temperature and glaciers in the Aurland river basin

Abstract

From 1973 onward the development of the Aurland power scheme has had a marked influence on the discharge into the Aurland river, resulting in a much lower volume of runoff in the spring and summer months. The water temperature has also been influenced so that the average summer temperature is lowered by as much as 2°C in August downstream of the Vassbygdvatn lake. On the stretch upstream of the lake, however, the summer temperature has increased somewhat. There are nine glaciers in the Aurland drainage basin. Repeated mapping of two of the glaciers (Storskavlen and Svartavassbreen) in 1969 and 1989 has shown that Storskavlen in this period decreased in volume, whereas Svartavassbreen increased. Different exposure of the glacier's surfaces seems to result in some differences in the amount of wind-blown snow that accumulates during the winter. A change in the dominating wind pattern during recent years seems to have brought relatively more snow to Svartavassbreen.