In mountainous and foothill areas, the formations of mudflows are possible. Mudflows are one of the most dangerous processes occurring in these areas. In this regard, the assessment of mudslide zones and mountain stream basins is crucial for ensuring safety in the development of mountain territories, especially in conditions of intensive technological progress. At the same time, the ability to assess the level of mudflow hazard has both theoretical and practical importance, since it allows you to assess the level of safety of existing or planned construction facilities on a given territory. The purpose of this work is to study the SPH-based model for modeling complex dense granular flows with a free surface.