Author(s): Delaram Kazemian; Knut Alfredsen
Linked Author(s): Knut Alfredsen
Keywords: River ice; Alberta’s River 1D ice model; Ice formation; Ice cover; Hydropower
Abstract: The Orkla River, located in Norway, is a important river system known for its diverse hydrological characteristics and significant ecological value. Situated in the central part of the country, the Orkla River flows through the counties of Trondelag and Innlandet. It spans approximately 179 kilometres, originating from the high mountain areas around Orkelsjoen and flows into the Trondheimsfjord. The river was regulated for hydropower in the 1980s and hydropower operation has changed the seasonality of flow and water temperature. With the current regulation, we have several hydropower outlets and a river intake on the main river in the Orkla valley, creating a variable hydrological regime in the river that differs from the natural winter conditions. River ice dynamics play a crucial role in the hydrological and ecological processes of cold regions, impacting water flow, flood risk, and habitat availability. Regulation for hydropower is known to influence river ice and this is also the case in Orkla, having effects both on the physical conditions in the river and on the operation of the hydropower plant. This paper presents a study on modelling ice in the Orkla River using the University of Alberta’s River 1D ice model. This paper describes the setup of the model and how it is adapted to the winter conditions in river Orkla on the reach between the outlet of the Grana power plant and the intake to Svorkmo power plant. The model is calibrated and validated using observed data, including observed drifting and temperature and discharge measurements to ensure its accuracy in simulating the ice dynamics specific to the Orkla River.
Year: 2024