Flash Flood struck Dhauliganga valley on February 7, 2021: A Case study of Chamoli district of Uttarakhand Himalaya in India

Abstract

Combining effects of prolonged rock fall, glacier avalanche, multiple damming of streams, rapid erosion of slope materials and sudden rise in temperature witnessed a flash flood situation on 7 February, 2021. Aftermath of initial incidence which was occurred in the morning 1015 hours at upper reaches of Raunthi Gadhera, within 30 minutes Rishiganga, Dhauliganga and Alaknanda rivers swelled enormously. Unprecedented discharge of the same washed off functional Rishiganga hydroelectric project of 13.2 MW capacity on Rishiganga near Rini while badly damaged under construction hydropower project of 520 MW of National Thermal Power Corporation at Tapoban on Dhauliganga river. Except for, 5 pedestrian bridges in various places over Dhauliganga river along with one motorable RCC bridge over Rishiganga at Rini leading to Joshimath - Malari State Highway were swept away in flash flood wherein disrupted the connectivity along with other supply of 13 villages. This caused heavy damage to life and property, particularly in these hydropower project sites. As many as 204 persons went missing, of these bodies of 77 persons could be recovered along with 12 persons injured and 184 farm animals were lost in this incidence. The aim of the present research is to examine the possible causes of the rock fall and flash flood together with their destructive effects. This work also focuses on present risk scenario and suggestions for disaster risk reduction within the affected region.

Keywords

• Rock fall
• Flash flood
• Losses
• Damages
• Changes in river morphology
• multiple damming
• Higher Himalaya

References

1. [1] C. Samela, S. Manfreda, F. D. Paola, M. Giugni, A. Sole and M. Fiorentino, “DEM-based approaches for the delineation of flood-prone areas in an ungauged basin in Africa,” Journal of Hydrologic Engineering, pp. 1-10, 2015.
2. [2] H. Aksoy, V.S.O. Kirca, H. I. Burgan and D. Kellecioglu, “Hydrological and hydraulic models for determination of flood-prone and flood inundation areas,” The 7th International Water Resources Management Conference of ICWRS, 18-20 May 2016, 373, pp. 137-141, Proceedings of the International Association of Hydrological Sciences (IAHS), Bochum, Germany, 2016.
3. [3] Sushil Khanduri, “Natural Hazards in the township of Nainital, Uttarakhand in India,” International Journal of Engineering Applied Sciences and Technology, Vol. 3, Issue 12, pp. 42-49, 2019.
4. [4] J. Xu, R. E. Grumbine, A. Shrestha, M. Eriksson, X. Yang, Y. Wang and A. Wilkes, “The melting Himalayas: Cascading effects of climate change on water, biodiversity, and livelihoods,” Conservation Biology, Vol. 23, pp. 520–530, 2009.
5. [5] S. L. Gariano and F. Guzzettai, “Landslides in a changing climate,” Earth-Science Reviews, 162, pp. 227-252, 2016.
6. [6] Sushil Khanduri, “Cloudbursts Over Indian Sub-continent of Uttarakhand Himalaya: A Traditional Habitation Input from Bansoli, District-Chamoli, India,” International Journal of Earth Sciences Knowledge and Applications, Vol. 2, pp. 48-63, 2020.
7. [7] Piyoosh Rautela, “Lessons learnt from the deluge of Kedarnath, Uttarakhand, India,” Asian Journal of Environment and Disaster Management, Vol. 5, pp. 167 – 75, 2013.
8. [8] S. Khanduri, K. S. Sajwan, A. Rawat, C. Dhyani, S. Kapoor, “Disaster in Rudraprayag District of Uttarakhand Himalaya: A Special Emphasis on Geomorphic Changes and Slope Instability,” Journal of Geography and Natural Disasters, Vol. 8, Issue 1, pp. 1-9, 2018.

9. [9] S. Khanduri, “Landslide Distribution and Damages during 2013 Deluge: A Case Study of Chamoli District, Uttarakhand,” Journal of Geography and Natural Disasters, Vol. 8, Issue, 2, pp. 1-10, 2018.
10. [10] Sushil Khanduri, “Disaster Hit Pithoragarh District of Uttarakhand Himalaya: Causes and Implications,” Journal of Geography and Natural Disasters, Vol. 7, pp. 1-5, 2017.
11. [11] Sushil Khanduri, “Formation and Failure of Natural Dams in Uttarakhand Himalaya: An Observation from Lwarkha, Chamba Tahsil of Tehri Garhwal District, India,” International Journal of Earth Sciences Knowledge and Applications, Vol. 3, pp. 12-22, 2021.
12. [12] K. S. Valdiya, “Damming rivers in the tectonically resurgent Uttarakhand Himalaya,” Current Science, Vol. 106, No. 12, pp. 1658-1668, 2014.
13. [13] P. Rautela and R. K. Pande, “Non-monsoonal landslides in Uttaranchal Himalaya (India): Implications upon disaster mitigation strategy,” Disaster Prevention and Management, Vol. 15, pp. 448 – 460, 2006.
14. [14] IS 1983, “Indian Standard (IS):1893, Part 1, Criteria for earthquake resistant design of structures,” Bureau of Indian Standards, New Delhi, 2002.
15. [15] J. R. Kayal, “Himalayan tectonic model and the great earthquakes: An appraisal; Geomatics,” Natural Hazards and Risk, Vol. 1, pp. 51–67, 2010.
16. [16] A. Heim and A. Gansser, “Central Himalaya: geological observations of the Swiss expedition 1936,” Memoir Society Helvetica Science Nature, 73, pp. 1–245, 1939.
17. [17] K. S. Valdiya, “Geology of the Kumaun Lesser Himalaya,” Wadia Institute of Himalayan Geology, Dehra Dun, India. 249p, 1980.
18. [18] K. S. Valdiya, “Trans-Himadri intracrustal fault and basement upwarps south of Indus-Tsangpo Suture Zone,” In Tectonics of Western Himalaya (eds. L.L. Malinconico and R.J. Lillie). Geological Society of America (Special Papers), Vol. 232, pp. 153–168, 1989.
19. [19] A. K. Jain, M. Shreshtha, P. Seth, L. Kanyal, R. Carosi, C. Montomoli, S. Iaccarino and P. K. Mukherjee, “The Higher Himalayan Crystallines, Alaknanda – Dhauli Ganga Valleys, Garhwal Himalaya, India,” In (Eds.) Chiara Montomoli, Rodolfo Carosi, Rick Law, Sandeep Singh and Santa Man Rai, Geological field trips in the Himalaya, Karakoram and Tibet, Journal of the Virtual Explorer, Vol. 47, pp. 1- 38, 2014.
20. [20] D. Petley, “The catastrophic landslide and flood in Chamoli in Uttarakhand: the sequence of events,” The Landslide Blog, AGU Blogosphere, blogs.agu.org/landslideblog/20, 2021.
21. [21] A. B. Shrestha, J. Steiner, S. Nepal, S. B. Maharjan, M. Jackson, G. Rasul and B. Bajracharya, “Understanding the Chamoli flood: Cause, process, impacts, and context of rapid infrastructure development,” RIVER BASINS AND CRYOSPHERE, ICIMOD, Kathmandu, Nepal, 2021.