A Case Study of the 12 July 2021 Bhagsunath (McLeod Ganj) Flash Flood in Dharamshala, Himachal Pradesh: A Warning Against Constricting Natural Drainage

Abstract

Extreme rainfall events leading to the occurrence of flash floods and cloudbursts are common in the Himalaya. Bhagsu nala in McLeod Ganj area of Dharamshala township, Himachal Pradesh has witnessed the worst flash flood in the morning of 12^th July 2021 causing damage to property and infrastructure in the region. Though the catchment area of the Bhagsu nala is very small of the order of ∼2.8 km², the geomorphological and hydrological characteristics of the catchment are susceptible to peak flow for a shorter duration. Further, the anthropogenic intervention of slopes in the form of constricting natural drainage has reduced the carrying capacity of the nala, exaggerating the consequences of the flash flood.