ISSN 2348-1218 (print) International Journal of Interdisciplinary Research and Innovations ISSN 2348-1226 (online) Vol. 8, Issue 2, pp: (8-16), Month: April - June 2020, Available at: www.researchpublish.com
Increasing Incidences of Cloudburst Triggered Debris-Flows/Flash Floods in Garhwal Himalaya, India Vishwambhar Prasad Sati Department of Geography and Resource Management, Mizoram University (A Central University), Aizawl – 796004, India Email: sati.vp@gmail.com
Abstract: This study examines the increasing incidences of cloudburst triggered debris-flows/flash floods in the Garhwal Himalaya, India. Data were gathered through the case studies of three incidences that occurred during the monsoon season – July, August, and September 2019. A total of 24 people died and 39 people were injured due to the cloudburst triggered debris-flows and flash floods events during the period. Further, about 150 roads were blocked and several houses, cowsheds, and agricultural land were drowned during the same time. This study reveals that most of the death and loss of property occurred along the river valleys because of the construction of houses on the fragile landscapes of these rivers’ banks. This study suggests that the construction of settlements should be avoided along the river valleys or on fragile landscapes. Economic activities should also be avoided in these fragile locations. Keywords: Debris-flows, flash floods, cloudburst, Garhwal Himalaya.
1. INTRODUCTION Cloudburst can be defined as a sudden heavy rain shower that occurs within a particular space and a short span of time (Sati and Maikhuri 1992). It triggers the occurrences of huge debris flows and flood floods. Debris flows and flash floods are synonymous. However, the amount of debris and water distinguishes them. Flash floods mainly occur along the river valleys, both sides of the streams whereas debris flows occur along the hill slopes, which comprise high slope gradients and fragile landscapes. Both debris flows and flash floods are very common, frequent and intensive in the Garhwal Himalaya and as a result, the entire region is worst affected. These hazards become more violent/disastrous, when they occur in the human settlements, cause the death of humans and animals, and the loss of properties and infrastructure. The high landscape fragility, instability of terrain, and intensive anthropogenic activities accentuate the magnitude of debris flows and flash floods, causing serious environmental degradation and huge loss of lives and property (Sati 2008). Every year, several debris flows and flash floods events occur in the Garhwal Himalaya. These events are accounting for more than 70% of all the economic losses and more than half of the casualties (Sati 2011). In the recent past, the Garhwal Himalaya has received high climate variability and change. The valley regions are warming and the middle altitude and the highlands are affecting with intensive and scanty of rainfall. High variability and change in climate have increased the frequency and intensity of rainfall, leading to flash floods and landslides in the Garhwal Himalaya (Chalise and Khanal 2001; ICIMOD 2007; ICIMOD 2007; Bhandari 1994; Kumar et al 2006; Uttarakhand 2017; Ives and Messerli 1989; Solomon et al 2007; Du et al 2004; Bandyopadhyay 1994; Sati 2013) during the recent past. The Garhwal Himalaya of the Indian Central Himalayan Region (ICHR) is one of the most fragile landscapes, which is highly vulnerable to natural hazards. It receives heavy rainfall mainly during the three months of monsoon season – July, August, and September, every year. There are several rivers – the Yamuna River and its tributaries, the Bhagirathi River and its tributaries and the Alaknanda River and its tributaries – originate and flow in the Garhwal Himalaya and many of
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