PRELIMINARY STUDY OF PREDICTION MODEL FOR EARLY WARNING OF DEBRIS FLOW

On 13th August 2010, large numerous debris flows occurred due to high intensity rainfall in Longchi area of Dujiangyan city. These disastrous debris flows brought heavy damage to reconstruction of the earthquake damaged region. It is very important to study the formative mechanism and early mitigation warning of the debris flows in this area. Based on the research achievements of predecessors such as occurrence and rainfall condition, this paper reveals that the water content of sediments and the depth of surface runoff are important factors to the initiation of debris flows. According to the characteristics of antecedent rainfall and effective rainfall intensity when debris flows occur, this paper establishes an initiation model of debris flow in this region. It is related to three grades of soil particle initiation processes. They are individual, partial, and whole grades. The different rainfall conditions are divided into blue, yellow and red three risk levels for this area of debris flow monitoring and early warning.