Hydraulic determination of dam releases to generate warning waves in a mountain stream: performance of an analytical kinematic wave model

In this case study, we study the generation of warning waves with prescribed characteristics in a mountain stream. We determine which dam release will generate the desired warning wave. We solve this inverse problem following a two-model approach. An analytical kinematic model is used for a preliminary design of the dam release and a detailed two-dimensional (2D) fully dynamic model is used to converge to the final solution. Although the presented case study is far from an idealized academic case, the analytical model performs well and, beyond its role for preliminary design, turns out to be of prime interest for both understanding and discussing the results of the detailed 2D model. The complex interactions between the release hydrograph, the geometry of the river and the friction formula are brought to light by the analytical model, which highlights the complementarity of both models and the usefulness of such a two-model approach.