Norwegian perspective on hydropower and recent research on the effects of flow contraction on spillway capacity.

Hydropower is the backbone of Norwegian electricity generation and has historically been one of the root causes of industrialization and the creation of the welfare system. This talk will outline the hydropower development of Norway and present the current trends and potential future developments. Increasing flood magnitudes and frequencies due to climate change place greater demands on dam safety and spillway capacity. In run-of-river systems, spillway capacity can be reduced by flow contraction and associated hydraulic losses. Experimental studies at NTNU show that contraction losses for ogee spillways can exceed values assumed in common design guidelines, indicating that a precautionary measure needs to be taken over the existing design practices. The results also indicate that the design capacity of the spillway can be restored through some minor mitigation measures and design alterations.