One focus of SFB 1313 is the development of project-area-specific, interface-related, scale-dependent model concepts and mathematical and numerical methods. In this task force, the mathematical and computational models for Project Areas A, B and C are discussed beyond the boundaries of each individual area. The aim is to develop and analyse joint conceptual models. One important aspect is the development of general models which bridge the gap between the different project areas. Based on this, further steps are taken towards creating an integrative perspective, resulting in a more generalised model description. For example, can we integrate the new free-flow porous-media interface concept directly in a phase-field model for fracture propagation?