Experiences from North America, Japan and Europe have proven that flexible protection systems have an ideal bearing behavior to stop dynamic loads such as debris flows due to their large deformation capacity and permeability to water. Similar to rockfall loads, debris flows act mainly dynamically on a protection barrier. Although in contrast to falling rocks, debris flows impose not a punctual impact but a distributed load on the protection system. Therefore, structural adaptations compared to a typical rockfall protection are unavoidable in order to achieve a reliable protection system against debris flows such as special rope guiding details, abrasion protection etc. This report summarizes the results of a research project that aimed the development of a dimensioning concept for flexible debris flow protection systems. The concept results on specially focused research combining laboratory tests, fully instrumented field installations and corresponding numerical simulations. The report is meant to form a basis that enables engineers or other people in the field of natural hazards to calculate and understand the design of flexible barriers against debris flows within channelized river beds.