(Feature image: Video grab of artificial lake on Chenab river. Source Weatherman Shubham @shubhamtorres09, Twitter, Aug. 16, 2022)
Debris brought by flash flood in Jahlma nullah blocked[i] the flows of Chenab (Chandrabhaga) river for about 6 hours in Udaipur tehsil of Lahual and Spiti district, Himachal Pradesh forming a huge lake. The incident occurred following heavy rainfall on August 15, 2022 night.
The blockage took place near Dara hills downstream Jobrang bridge. The artificial lake started forming around 05:00 am and water level kept rising till 11:00 am before it breached naturally[ii] draining out the lake by 02:00 pm.
But before the breach, the water impoundment of the Chenab had submerged[iii] adjoining agricultural lands in Jobrang. The flash flood in Jahlma nullah also reportedly changed the course[iv] of the river and damaged farming lands and apple orchards belonging to Halling and Jasrath villages.
The visuals of the site showed the backflow almost touched the Jobrang road bridge and partly submerged Jobrang foot bridge. The foot bridge as Jasrath has been damaged and facing collapse while a part of road along Jahlma nullah has caved in affecting traffic following the incident.
The administration took cognizance of the matter and subsequently sounded alert in vulnerable area. As per Manav Verma, SP, Lahaul, the river had naturally made a path[v] to release the water. However, villagers feared that a sudden breach[vi] could create flash flood destruction in downstream areas upto Udaipur.
The Google Earth imagery shows three streams (Dara waterfall from left bank & Jahlma and one other stream from left bank) joining the Chenab river at obstruction site.
Drainage map of Jahlma nullah. Source:- Land use and land cover changes in Jahlma watershed of the Lahaul valley
The area is disaster prone and has been facing landslide, flash flood, cloudburst[vii] destruction in the recent past. On August 13, 2021 a landslide lake had formed[viii] on the river just about two and half km upstream from the present location.
The government has planned series of hydro power projects on Chenab and key tributaries in this disaster prone valley. On the other hand the ground realities and repeated disasters have been warning and warranting a serious relook on these unviable proposed projects.
Bhim Singh Rawat (bhim.sandrp@gmail.com)
References:
[i] https://twitter.com/shubhamtorres09/status/1559354838554537986?s=20&t=4dL2ZkyG0vN2BMxWgtBCGg
[ii] https://himachal.punjabkesari.in/himachal-pradesh/news/chenab-s-flow-stopped-due-to-flood-in-jahlma-drain-1656635
[iii] https://www.etvbharat.com/hindi/himachal-pradesh/videos/top-videos/flood-in-jahlma-drain-of-lahaul-valley-flow-of-chandrabhaga-river-stopped/hp20220816092854225225120
[iv] https://hindi.news18.com/news/himachal-pradesh/manali-monsoon-rain-chandra-bhaga-river-water-flow-blocked-due-to-flash-flood-in-jahlama-nallah-in-lahaul-spiti-hpvk-4473082.html
[v] https://himachalabhiabhi.com/flood-in-chandrabhaga-river-himachal-pradesh/
[vi] https://www.amarujala.com/shimla/flood-in-jahlma-drain-of-lahaul-spiti-flow-of-chandrabhaga-river-stopped
[vii] https://www.outlookindia.com/website/story/india-news-10-missing-1-injured-in-flash-floods-due-to-cloudburst-in-himachal-pradesh/389642
[viii] https://sandrp.in/2021/08/14/landslide-dam-on-chenab-river-in-himachal-pradesh/
SANDRP 