Gully characteristics across linear troughs in the southern Daliangshan, and its implications for debris mitigation

Characteristics of large-scale landforms have been widely studied due to their importance for understanding the interaction between tectonics and climate changes. However, increasing studies suggest that localized landforms, previously poorly focused, is more helpful for revealing mechanisms of geologic hazards and can provide insights for making mitigation schemes. This paper used the linear trough at three sites developed on the southern Daliangshan, southeastern Tibetan Plateau as an example, to provide implications for choosing a safer construction site in topographic relief region. Based on field investigations, geomorphic analysis, and numerical simulation, we suggest that characteristics of gullies have been affected by the linear trough. The three gullies above the trough show a normal sequence in hillslope angles, which is consistent with the width of the corresponding outlets at the linear trough. Conversely, the part below the trough along the gullies show a reversed sequence in hillslope angles for the three sites. The aforementioned characteristics are further evidenced by the numerical simulation by PFC3D. Therefore, we suggest that linear troughs can be considered natural barriers that hinder transportation of the gullies, which might provide some new insights for gully-related debris mitigation in mountainous areas.