Simulation and modeling of debris flows using satellite derived data: A case study from Kedarnath Area

Comprehensive assessment of landslide hazard requires process based modeling using numerical simulation methods. The present study aims to focus on analysis of landslides/debris flow movements and simulate landslides that occurred in Kedarnath area in June 2013. Although not widely discussed, these landslides were the prime cause of river blockade that contributed significantly in glacial lake outburst flood (GLOF) related disaster in and around Kedarnath. In the present study, the simulation was attempted by numerical modeling using Rapid Mass Movement Software (RAMMS). The algorithm is based on Voellmy frictional (dry and turbulent frictional coefficients, μ and χ) parameters of debris flow with release area that can be identified on high resolution satellite images and derived DEM like Cartosat-1 DEM. Once the event is simulated model provides information on flow 1) Velocity, 2) Height, 3) Momentum, and 4) Pressure along the entrainment path. The main emphasis was to understand on how closely numerical simulation predicted the attributes of the landslides/debris flow that contributed to the unprecedented disaster in Kedarnath. This study revealed that simulated flow height at base of the entrainment to vary from 1m to 6m and flow velocity varying from 3 to 7m/s. These vital output parameters can be used to provide insight of the event and extent of run out zone of future potential flows. Thus, this work bespeaks that numerical simulation modeling is capable of emulating natural events and outputs can be used for mitigation measures.