Integrated disaster mitigation needs interpreting torrent catchment areas as complex landscape systems. The history of valley-evolution shows the influence of climate and vegetation on the valley-evolution. The energy-concept (energy dissipation concept including the idea of the energy-line) is used for a simple explanation of debris flow. Examples of heavy debris flow disasters in controlled torrents in the Alps and Pyrenees give hints, which expanding the time scale can show that side-effects restrict or counteract the mitigation measures. A pallet of different mitigation measures to avoid or to reduce some of the side-effects is shown. The comprehensive method of disaster mitigation also includes the effect of vegetation. The pallet includes: avoiding hazards (hazard mapping, warning and alarming), appropriate land use and avoiding disaster-enhancing measures in the landscape and technical measures, which take into account their side-effects. The energy line is used as simple design theory. The Jiu-Jitsu Principle is explained too. With this comprehensive method a more sustainable reduction of disasters seems possible. Integrated disaster mitigation needs interpreting torrent catchment areas as complex landscape systems. The history of valley-evolution shows the influence of climate and vegetation on the valley-evolution. The energy-concept (energy dissipation concept including the idea of ​​the energy-line) is used for a simple explanation of debris flow. Examples of heavy debris flow disasters in controlled torrents in the Alps and Pyrenees give hints, which expanding the time scale can show that side-effects restrict or counteract the mitigation measures. A pallet of different mitigation measures to avoid or to reduce some of the side-effects is shown. The comprehensive method of disaster mitigation also includes the effect of vegetation. Measures in the landscape and technical measures, which take into account their side-effects. The energy line is used as simple design theory. The Jiu-Jitsu Principle is explained too. With this comprehensive method a more sustainable reduction of disasters seems possible.