Author(s): Knut Tore Alfredsen

Linked Author(s): Knut Alfredsen

Keywords: Hydropower; Hydrology; Environmental impacts; Bypass reaches; Flood regimes

Abstract: Norway has several large high-head hydropower systems with multiple reservoirs and a network of brook intakes altering the natural flow regime and leading to a several changes in the physical environment in the river system affected by the regulation. Due to intake and release of water at many locations, such systems might have different flow regimes at different locations in the water course, and the impacted reaches might be many kilometers long. Here we have investigated the impacts of the regulation of the Lærdal river and evaluated the effects on the flow regime and other associated physical features like water temperature, river ice formation and river morphology after 50-years of regulation. The findings are discussed and related to other similar systems to look for patterns and typical regulation effects. Given plans for upgrades and changes in future operational strategies in Norwegian regulated rivers, understanding the scale and type of impact will be important for future mitigation measures.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.145

Year: 2026