Dams in Chenab Basin and Climate Change: Need to Exercise Caution

Hydropower Projects in Chenab basin - Commissioned in Red, Under-construction in orange and Planned in yellow

By SANDRP on April 27, 2025. (released again on 5 May 2025)

The current developments around Indus Waters Treaty are deeply troubling. Following the heinous attack on tourists in Pehelgam, India has announced that Indus Waters Treaty, the only water sharing mechanism between India and Pakistan put in place in 1960, has been suspended.

While this announcement implies several things that India can do, one of the ‘tools’ being highlighted is more infrastructure ( read Dams) on these rivers as soon as possible[i].  Pakistan has stated that suspending IWT is an ‘Act of War’.

But there is already a war going on in the Indus basin right now that has claimed hundreds of lives on both sides of the border (3 people, just four days back[ii]), has driven people destitute and homeless, affected crops and livelihoods. That war is in the form of Climate Change, repeating disasters and the massive changes in hydrology in Indus basin in general and Chenab Basin in particular. Chenab Basin has the largest number of completed, under-construction and planned hydropower projects among the Western Rivers of the Indus basin in India and is therefore significant.

Any hasty plans to push further dams, completing construction of ongoing projects in a rush, bypassing important studies and safeguards around dams, ignoring local protests which are fueled by repeated disasters, is extremely dangerous in this region.

We will briefly look at Climate Change and related disasters, Water Security, Hydropower development, governance around these issues and whether it is feasible, desirable or advisable to push for more dams in this region.

The report is based on extensive travel and fieldwork (October and Nov 2024) from origin of Chenab to Akhnoor where the river exits India, community interviews, review of government reports and scientific studies in the Chenab Basin.

1. Glaciers in the Headwaters of Chenab Basin

Chenab forms at the confluence of Chandra and Bhaga rivers in Lahaul and Spiti, Himachal Pradesh. According to the Indus Waters Treaty, Chenab is a Western River, allocated to Pakistan. India is permitted limited consumptive use and unlimited non-consumptive use of Chenab. Between the period IWT was signed to 2004-5, studies estimate that glacial volume in Chenab basin is reduced by a whopping 33.3% [iii] For a river whose flows are made up of 50% meltwater when it leaves India at Akhnoor, this is shocking for both India and Pakistan. Glaciers, the water stored in them, the slow release of this water in spring and summers is the key to water security of entire Himalayan region. 60% irrigation in entire Indus basin depends on glacial melt[iv]. As the glaciers are concentrated in Indian Himalayas, their health and sustenance is crucial for millions in both countries.

Let us look at both these rivers Chandra and Bhaga, which originate at around 15900 feet at Baralachala pass in the Greater Himalayas and especially glaciers and hydropower in these basins.

a. Bhaga Basin

Bhaga River originates near Surajtal lake. The region is home to over 306 glaciers (each with area larger than 200 sq mts), all of which are rapidly retreating. The total stored water of Bhaga Basin glaciers is estimated at approximately 15 Billion Tons.[v]

Not only has the total area covered by glaciers reduced between 1971 to 2020 but the rate of deglaciation “has increased significantly (0.25 % yr-1) compared to the previous decades.”[vi] Rate of change of glacier area has doubled in the last two decades.[vii] Temperature shows an increasing trend of about 1.14° Celsius between 1961 and 2015 and significant precipitation decrease from 1990s onwards which “have probably augmented ice loss in the Bhaga basin during the early 21st century.”[viii] Glaciers have undergone significant amount of mass loss and thinning.[ix] And scientists fear “At this rate of retreat, small glaciers (area less than 1 km2) will permanently disappear soon.”[x]

In 2018 a GLOF event occurred near Zingzingbar. The region routinely faces debilitating floods and landslides.

The massive 300 MW Gyspa Hydropower project is proposed at Gyspa village in Bhaga basin. It envisages a gross storage of 0.74 Million Acre Feet through a dam that will submerge 1260 hectares land and 4 villages including Darcha. Local population, especially women, have put up strong opposition to this project and one of the main reasons for doing so is increasing disasters in the region.[xi]

In 2018 a GLOF event occurred near Zingzingbar. The region routinely faces debilitating floods and landslides.

The massive 300 MW Gyspa Hydropower project is proposed at Gyspa village in Bhaga basin. It envisages a gross storage of 0.74 Million Acre Feet through a dam that will submerge 1260 hectares land and 4 villages including Darcha. Local population, especially women, have put up strong opposition to this project and one of the main reasons for doing so is increasing disasters in the region.[xi]

b. Chandra Basin:

Chandra basin occupies an area of 2,440 sq km area and has around 200 glaciers and 23 small villages.[xii] It is home to some of the largest glaciers in Himachal Pradesh like Bara Shigri, Ghepan Gath and Samudra Tapu, all of which show alarming climate change impacts.

Even in moderate emission mitigation scenario, the basin is projected to lose 33% of its ice volume by 2050s. That is a loss of 17.7 Billion Tons of Ice.[xiii]

Studies predict that “In response to the projected climate, the basin is likely to retain only ~ 50% (In moderate mitigation scenario[xiv]) and ~40% (in business-as-usual scenario[xv]) area of glaciers by the end of the century.

Corresponding volumes of glacier water retained are much lower at~ 40% and ~30%  but the volume loss could be as high as 97% for low altitude glaciers.”[xvi]

From 2000 to 2014, the total number of glacial lakes in Chandra basin (larger than 2000 sq mts) increased from 28 to 46 and their area expanded from 1.91 sq km to 3.26 sq km. The accelerated growth of glacial lakes has resulted in increased hazard and damage potential of glacial lake outburst floods.[xvii]  And “Glacial Lake Outburst Flood (GLOF) is an emerging threat in the Chandra basin.’[xviii]

Samudra Tapu Glacier and Glacial Lake

• India’s premier remote sensing institute National Remote Sensing Centre (NRSC) under the aegis of Indian Space Research Organization (ISRO) in its 2024 report on Samudra Tapu Glacial Lake states[xix], “A change analysis of the lake water spread area carried out in 1965 and 2022 satellite imagery revealed a 905% increase in size from 14.19 ha to 142.69 ha. Such alarming rate of lake expansion and growth of its downstream settlements have increased the possibilities of a catastrophic impact due to GLOF event by many folds.”

• The estimated discharge at 100% breach of the lake is 17,342 cumecs (cubic Meters per second) and will affect settlements far and wide along the Chenab.

• Studies also show that such a GLOF will be a threat to life and property to villages downstream like Chhatru[xx]  where 126 MW Chhatru Hydropower Project is proposed and has received Environmental Clearance in 2015.[xxi] Any hydropower project in such a remote location threatened with GLOFs poses a threat not only to the settlement but also to the workers at the project site.

Bara Shigri Glacier and Glacial Lakes

• Bara Shigri, the largest glacier in Chenab Basin and Himachal Pradesh is receding rapidly and has lost about 4 sq kms area in the last century, with accelerated loss in the latter part of last century. [xxiii]According to IPCC’s Fourth Assessment Report, [xxiv]Bara Shigri’s snout shows a retreat of 650 meters between 1977 & 1995, averaging to 36.1 meters retreat annually.

• More than 60 ice-dammed (supraglacial) glacial lakes have formed on the debris (rocks, sediments and ice) covering the glacier.[xxv] These lakes are volatile and highly susceptible to climatic changes.

Ghepan Gath Glacier and Glacial Lake

Downstream of Bara Shigri is the Ghepan Gath glaciers and lake, which is one of the fastest-growing glacial lakes in India.[xxvi] The NRSC-ISRO study states, “A change analysis of the lake water spread area carried out between 1989 and 2022 imagery revealed a 178% increase in size from 36.49 ha to 101.30 ha. Such alarming rate of lake expansion and the increase in its downstream settlements have increased the possibilities of a catastrophic impact due to GLOF event by many folds.”[xxvii]

Studies indicate that the lake will double its size in the near future and poses a very serious GLOF risk and threat to life and property to the downstream village of Sissu, its river camping grounds and tourist accommodations.[xxix] “Sissu is potentially exposed to high-intensity glacial lake outburst flood hazard under all current scenarios and the moderate and large magnitude in future scenarios.”[xxx]

2. Drying springs, changes in irrigation and water security issues in the Chandrabhaga Basin

In the villages like Tandi and Tholang, irrigation is shifting away from groundwater springs or glacial melt. New Lift irrigation schemes based on the river are being set up by farmers as well as the Irrigation and Public Health Department to counter drying springs.  Conflicts between farmers in the upstream and downstream are becoming more common due to this.

Scientific studies support primary observations. “Snowfall has decreased in Lahaul-Spiti in the last three to four decades resulting in a water scarcity. The decreasing snow cover area in the region can be linked to the broader impact of climate change. Rising temperatures, changes in precipitation patterns, and altered snowfall contribute to reduced snow accumulation and earlier melting.” In this study, 70% respondents (Sample size of the study was more than 500) “noted dried water sources and extreme weather events, indicating concerns over water security and environmental stability.”

3. Hydropower Projects surrounding Tandi

Despite the concerns and fears of local communities and scientific studies, three large hydropower projects are proposed in the 44 kms between Tandi and Udaipur. They are 104 Tandi HEP, 130 MW Rashil HEP and 175 MW Bardang HEP.

The proposed projects are making the communities restive and several villages have documented their protests against the hydropower projects under the aegis of Save Lahaul Spiti Society and Tandi Bandh Sangharsh Samiti (Committee against Tandi Dam). We witnessed several boards set up by the communities which forbid any dam-related activity in their villages.

Main contentions are increasing climate disasters in Lahaul, disasters around hydropower projects in Himalayas and loss of limited fertile valley land along the rivers.

Nallahs like Jahlma are flooding even when there is no rain, resulting in massive landslides that engulf fields and block the flow of mainstem Chenab for hours. Hydropower projects planned close to this site can cause critical issues to communities. Our report here: https://sandrp.in/2025/04/17/a-sinking-village-a-stream-that-floods-in-the-sun-climate-change-jahlma-nallah-and-lindur-in-chenab-basin/  

4. Miyar Basin Glaciers and Hydropower Project

Downstream from Tandi near Udaipur, Miyar Nallah is fed by Miyar glacier, at an altitude of 4200 mts[xxxi]in the Greater Himalayas.[xxxii] Miyar basin has 156 glacial lakes: highest concentration of glacial lakes in the Chandrabhaga/Chenab basin.[xxxiii] The basin is home to 120 glaciers covering an area of 314 sq kms.

Miyar basin and especially its Karpat Nallah catchment[xxxiv] has seen repeated floods, landslides and disasters which isolate the valley, cutting off its access from Udaipur and the main highway for days at end. Devastating floods have been recorded in the Miyar basin in 2013[xxxv], 2014, 2017[xxxvi], 2023[xxxvii] and 2024[xxxviii].

In this flood-prone basin with high concentration of glacial lakes and repeated flood losses to the community, 120 MW Miyar Hydropower Project has been proposed. The dam site near Shakoli village is barely 10 kms from disaster- ravaged Karpat and Changut. The project received Environmental Clearance in 2012, based on the Environmental Impact Assessment carried out even before 2012. However, in March 2025, Himachal Pradesh Government signed a Memorandum of Understanding with Telangana State Government develop the Miyar Project.[xxxix] Shockingly, the EC letter does not make any mention of Miyar Glacier, glacial lakes, flooding events, possible protective measures to be carried out by the project etc.

Source: https://mail.google.com/mail/u/0/#inbox/FMfcgzQbdrRZwrwqDhJxlBLBCBsKBpTk