Impulse waves at Kühtai reservoir generated by avalanches and lindslides

The Kühtai reservoir is planned as an addition to the existing Sellrain-Silz group of HPPs. Two natural hazards relevant in terms of potential impulse wave impact on the dam were identified: a snow avalanche near the dam axis and a possible landslide further upstream. A preliminary analytical evaluation of impulse wave heights and wave run-up based on empirical equations showed that dam overtopping could not be excluded. However, several limitations of this evaluation were not satisfied, resulting in a reduced validity of the prediction. Thus, impulse wave generation was investigated in a 1:130 hydraulic scale model. Beside tests related to the relevant events, an additional systematic parameter variation validated the quality of the results. However, as no overtopping occurred even for the parameter variation, no measures such as breakwater or increase of the freeboard were required. The model test results are compared to a further analytical evaluation based on the recently published VAW-manual on landslide generat-ed impulse waves.