Coupling glacier and debris flow processes to long-term landscape evolution model for drainage divide migration

Both glaciers and debris flows can shape the landscape in high mountain areas close to drainage divides. As the glacier erodes the landscape, it leads to drainage divide migration and an asymmetric landscape. During divide migration, catastrophic mass movement events, such as rock avalanches and debris flows, may intensify. The intensive erosion ability induced by debris flow could trigger effects on the landscape as well. However, we still cannot quantify the effects of debris flow on divide migration in glacier-dominated regions. Here, we propose a new numerical framework combining erosion from glaciers, fluvial processes, and debris flows in a long-term landscape evolution framework. Our preliminary results show that debris flow processes can slow down divide migration speed within the glacier-dominated regions. An intensive erosion ability of debris flow can make the divide move to the glacier side. Under the effects of debris flow, the effects trigger a longer glacier response time. Debris flow and glacier work together to decrease the divide’s elevation. Our new model can help us to understand the effects of debris flows and glaciers on long-term landscape evolution under climate changes.