Rainfall and anthropogenically accelerated mass movement in the Outer Himalaya, north of Dharamshala town, Kangra district, Himachal Pradesh: A cause of concern

Abstract

The present study has been done to evaluate the lithotectonic, geomorphic, hydrological and climatic factors responsible for the Tirah Line landslide, as well as, the anthropogenic factors that have augmented the damage potential of the slide. The town of Dharamsala and its suburbs in the Kangra valley provide a type example where unplanned development and urbanization has added to the hazard from landslides beside other factors. A devastating landslide occurred on 7th August, 2013 near Tirah Line locality of Dharamsala cantonment area, district Kangra, Himachal Pradesh, and damaged more than 25 houses completely. An estimated 0.1 sq.km of area of unconsolidated mass slid SSE down the terminal part of a thick alluvial fan on the left bank of the local drainage. The slide occurred after continuous heavy to very heavy rainfall for 4 days in August 2013 in the region when all the drainage remained in bankful position. Factors involved in slide were steep slope, continuous infiltration of water soak pits (sewage system) located up slopes, continuous heavy to very heavy rainfall and toe erosion by local drainage. The slide was moved in multiple phases due to continuous rainfall in the area.