Author(s): Reidar Dahl
Linked Author(s):
Keywords: No Keywords
Abstract: The river Orkla is one of the main rivers in Northern Central-Norway. The catchment area is 3000 km2, and the river is approx. 200 km long. The altitude range is from sea level to 1600 m above. The specific runoff is 25 1/sec/km2. The development for hydropower of Orkla caused the water discharge to vary greatly from one winter season to another in the years 1981-1984. Ice formation and erosion phenomena were studied at three gravel thresholds in the river during these winters. The ice at the thresholds was built up by anchor ice in cold weather early in the winter. The water concentrated in courses eroded in the ice during milder periods. At one of the thresholds, the water also eroded some of the gravel in the river bed. This was possibly due to the extra head of the water built up by the ice on the rest of the threshold. No erosion was observed elsewhere on the thresholds.
Year: 1986