///The Quaternary debris-flow accumulations can provide rich information for geomorphic evolution, tectonic movement and climate change. The Waka debris flows is one of the major debris flows in the river segment and has successive series in the exposed sections. Detailed granularity, pollen, geochemical and textural studies reveal the formation processes of Waka debris flows. The age estimates of optically stimulated luminescence (OSL) using SAR protocol show that the occurrence of major debris flows started at around 12.6 ka B. P. and weakened until 4.5 ka B. P. in the upper