Page - 1072 - in Book of Full Papers - Symposium Hydro Engineering

discharge. The readings will be compared to the physical model, and also the fluctuation of the water level. Figure 13: Drone photo from first discharge test, after completed construction (Norconsult, 2016). 5. CONCLUSION Both Långströmmen and Ramsele are high-hazard dams where recent dam safety revisions have uncovered deficiencies in their spillway structures. Whether the defects are in spillway capacity or in the structure downstream where scouring can erode the foundations of dam and spillway, one needs to fully understand the forces in play prior to designing the spillway structure. In this, the value provided by physical modelling has been underscored in both projects by findings during the project life. In Långströmmen, discoveries on site necessitated a revamp of the design. In Ramsele, the discoveries were in the model phase and the design could be adapted parallel to the model tests. In ideal worlds, the physical models should be kept until the project has been completed successfully. However, as large physical models are costly to keep for extended periods of time, the approach described in the Långströmmen project can be a way forward. 1072