Keynote lecture. Defining Protection Works Against Debris-Flow Hazards: Industrial Standard, Tailor-made or Haute-couture?

Abstract

Despite centuries of forestry and empirical soil conservation works as well as decades of research on debris flow processes, defining protection strategies against debris flows remains complicated. We are far from guidelines resembling an industrial standard to define the type, location and shape of debris flow protection works. We believe that this particular step will likely never be fully standardized because design engineers must have a certain degree of freedom to tailor the protection works to the astonishing varieties of catchments, geologies and geomorphologies, and the associated complex emerging debris flow regimes. Some catchments are have such specific features that defining an adapted protection strategy requires innovation: this is not even “tailor-made” but perhaps “haute-couture”. In this paper and the associated keynote lecture, we propose a possible way to approach the problem by firstly focusing on the sediment transport connectivity and the channel malfunctions leading to debris flow deposition; and secondly to select structures that prevent the latter, as well as to adjust the channel capacity to the debris flow supply.