Author(s): Helge Fuchs; Willi H. Hager
Linked Author(s): Willi H. Hager
Keywords: Impulse waves; Physical modeling; Solitary wave; Tsunami; Wave run-up
Abstract: Impulse waves are generated by landslides, rockfalls or avalanches impacting a reservoir or natural lake. The long waves generated by the impulse transferred to the water body in combination with the usually short propagation distance within a lake leads to a large damage potential due to wave run-up or dam overtopping. Fatal historic events occurred at Lituya Bay, Alaska, in 1958, or at the Vaiont Reservoir, Italy, in 1963. Recent events were observed at Lake Chehalis, Canada, or at the Nagatono Power Plant, Japan. Previous research at the Laboratory of Hydraulics, Hydrology and Glaciology (VAW) aimed at the generation phase of landslide-generated impulse waves with a special focus on the wave characteristics and the wave types. As a major result a computational guideline for impulse waves was published in 2008, which is an integral component of the short course on ‘Landslide generated impulse waves’ held on September 8, 2013, within the frame of the 35th IAHR World Congress. Physical model experiments were conducted in an 11 m long, 0. 50 m wide and 1 m deep wave channel. Testing involved a piston-type wave maker to generate solitary waves, three linearly inclined PVC shores with tanβ = 1/5. 0, 1/2. 5 and 1/1. 5, a still water depth of h = 0. 20 m, and relative wave heights H/h = 0. 1 - 0. 7. The maximum wave run-up heights, wave reflection coefficients and free surface profiles were evaluated from optical measurements.