Susceptibility assessment of rainfall induced debris flow zones in Ladakh–Nubra region, Indian Himalaya

• Published in: Journal of Earth System Science 2020-12, Vol.129 (1), p.30, Article 30
• Main Authors: Negi, H S, Kumar, Anant, Rao, N Narasimha, Thakur, N K, Shekhar, M S, Snehmani
• Format: Article
• Language: English
• Subjects: Accuracy; Debris flow; Detritus; Earth and Environmental Science; Earth Sciences; Geographic information systems; Geographical information systems; Heavy precipitation; Hydrologic data; Landslides & mudslides; Mathematical models; Multiple criterion; Precipitation; Precipitation forecasting; Rain; Rainfall; Rainfall amount; Rainfall data; Rainfall simulators; Satellite imagery; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Weather forecasting; Wind
• ISSN: 2347-4327; 0253-4126; 0973-774X
• DOI: 10.1007/s12040-019-1277-4

In recent past, rainfall-induced debris flow events in Ladakh–Nubra region have caused loss of lives and damages to civil infrastructures and army locations. Therefore, there is a need of high spatial and temporal monitoring of precipitation, and further to assess susceptible rainfall-induced debris flow zones in the area. We assessed the rainfall data collected at two gauge stations and observed a significant increase in the rainfall amount over the study region during summer-monsoonal period 1997–2017. Increasing trend was also observed from CRU gridded precipitation dataset. A GIS-based multi-criteria evaluation (MCE) method was performed by combining topographical, environmental and hydrological parameters for mapping of rainfall-induced susceptible zones. Suitability analysis of precipitation forecasts from WRF model at higher resolution (3 km) was also performed. A good agreement (r = 0.76) was observed between 4-day model forecast and field observed rainfall. Further, the simulated precipitation from WRF was incorporated into GIS model for assessment of debris flow susceptible zones for two cases of heavy precipitation events. The modelled high, medium, low and very low risk susceptible zones identified for the year 2015 events are validated with field survey and pre-post satellite imageries, and found in good agreement (ROC = 76.6%). The model was able to identify affected areas during the Leh cloud burst event in year 2010. In addition, a threshold value of rainfall for initiation of debris flow in the region was also reported.