Rainfall threshold calculation method for debris flow pre-warning in data-poor areas

Abstract

Debris flows are the one type of natural disaster that is most closely associated with human activities. Debris flows are characterized as being widely distributed and frequently activated. Rainfall is an important component of debris flows and is the most active factor when debris flows occur. Rainfall also determines the temporal and spatial distribution characteristics of the hazards. A reasonable rainfall threshold target is essential to ensuring the accuracy of debris flow pre-warning. Such a threshold is important for the study of the mechanisms of debris flow formation, predicting the characteristics of future activities and the design of prevention and engineering control measures. Most mountainous areas have little data regarding rainfall and hazards, especially in debris flow forming regions. Therefore, both the traditional demonstration method and frequency calculated method cannot satisfy the debris flow pre-warning requirements. This study presents the characteristics of pre-warning regions, included the rainfall, hydrologic and topographic conditions. An analogous area with abundant data and the same conditions as the pre-warning region was selected, and the rainfall threshold was calculated by proxy. This method resolved the problem of debris flow pre-warning in areas lacking data and provided a new approach for debris flow pre-warning in mountainous areas.

Keywords

rainfall threshold / debris flow / pre-warning / calculation method / data lack area

References

[1] Bai L P, Sun J L, Nan Y. Analysis of the Critical Rainfall Thresholds for Mudflow in Beijing, China. Geological Bulletin of China, 2008, 27(5): 674-680.

[2] Duan S R. Analysis on the Threshold of Mountain Torrents in Typical Small Watershed. Water Resources Planning and Design, 2009, 2: 20-22.

[3] Duan S R. Analysis on the Threshold of Mountain Torrents in Typical Small Watershed, Take Datong, a Branch of Yellow River, as an Example. China Rural Water and Hydropower, 2008, 8: 63-65.

[4] Hu M J, Wang R. Testing Study of the Correlation among Landslide, Debris Flow and Rainfall in Jiangjia Gully. Chinese Journal of Rock Mechanics and Engineering, 2003, 22(5): 824-828.

[5] Liang G M, Yao L K. Study to Determine the Critical Rainfall for Debris Flow. Subgrade Engineering, 2008, 6: 3-5.

[6] Lin X, Zheng Z Q, Huang W J. Relationship between Rainfall and Debris Flow in Dongchuan Area. Subgrade Engineering, 2001, 4: 10-14.

[7] Pan H L, Ou G Q, Huang J C, . Study of Rainfall Threshold of Debris Flow Forewarning in Data Lack Areas. Rock and Soil Mechanics, 2012, 7: 2122-2126.

[8] Su P C, Liu X L, Guo J. Primary Analysis of Relationship between Debris Flows and Rainfalls in Sichuan Province. Journal of Natural Disasters, 2006, 4: 19-23.

[9] Tian B, Wang Y Y, Hong Y. Weighted Relation between Antecedent Rainfall and Process Precipitation in Debris Flow Prediction—A Case Study of Jiangjia Gully in Yunnan Province. Bulletin of Soil and Water Conservation, 2008, 28(2): 71-75.

[10] Wang L. The Rainfall Situation and Debris Flow in Yutianqie River. Scientific and Technical Information of Soil and Water Conservation, 1996, 2: 29-31.

[11] Yao L K. A Research on the Calculation of Critical Rainfall with Frequency of Debris Flow and Torrential Rain. Journal of Soil and Water Conservation, 1988, 2(4): 72-78.

[12] Zhuang J Q, Cui P, Ge Y G, . Relationship between Rainfall Characteristics and Total Amount of Debris Flow. Journal of Beijing Forestry University, 2009, 31(4): 77-83.