One cloudburst - 2 dams destroyed?
Story of Malana Valley in Himachal Pradesh on the night of July 31-Aug 1, 2024.
(See post thread for images to help understand)
In a tragic replay of what happened in the Teesta River Valley in Sikkim in 2023, two hydro power projects have mostly been totally destroyed in the Malana rivulet valley on the night of July 31-Aug 1, 2024.
A total of 186 MW of power generation capacity and hundreds of crores of investment is probably gone.
All images and videos I have come across are of the storage unit of the Malana-I power project. Malana-II is apparently still inaccessible and there is no news of the situation there. Looking at the damages in the valley, it is highly unlikely that Malana-II has escaped unscathed.
The Malana rivulet originates from the Malana Glacier in the Beas basin in Himachal Pradesh. It flows quite rapidly downstream passing below the famous village of Malana to meet the Parvati River at Jhari. The Parvati then meets the Beas at Bhuntar.
Malana rivulet has two power projects built on it.
Malana-I - 86 MW and Malana-II - 100 MW. Malana-I is older than Malana-II.
Malana-II is upstream of Malana village and Malana-I downstream. Both the projects 'touch' each other. Malana-II ends just a few metres from where Malana-I begins. Malana-II was built because it was felt that the rivulet had potential to generate more energy.
Both the dams are technically 'run of the river' but have differing designs. Malana-II has bigger pondage than Malana-I. Interestingly, Malana-I has its powerstation on the banks of the Parvati River as its tunnel geometry brings it to the Parvati gorge. Malana-II's power station tucked behind the barrage of Malana-I, is not very visible in satellite pictures as the gorge is quite narrow.
Both the dams have had a troubled history - as is the case with all himalayan hydel projects.
Malana-I - has had very publicised issues with the foundation of its above-ground reservoir. the design of this project has water from the barrage flowing into de-silting ponds and then into an above-ground reservoir before entering the intake for the Head Race Tunnel. The above-ground reservoir is basically a concrete tank built in the bed of the rivulet - like a large swimming pool. The foundation of this tank has failed multiple times since 2001. It has leaked water and has been repaired many times.
Yesterday the de-silting ponds and the reservoir have been completely destroyed. You can hear in one of the disaster videos a person yelling dam has burst, he is speaking about this dam.
The barrage of Malana-I has a peak flood discharge capacity of 600 cumecs. It looks like it was overwhelmed completely for the ponds and reservoir to be destroyed. Malana-II upstream has flood discharge of 650 cumecs, just 50 higher than Malana-I. 50 cumecs will not cause damage like this, thus there was massive flow from upstream.
Malana-II - has had an equally troubled history and as recently as the cloudburst in the same rivulet in July 2023! Malana-II is a much bigger gravity storage pondage. Its floodgates jammed due to debris in 2023. It almost suffered an overtopping. Breaches were observed at the top of the dam. Lucky, it held. The jammed gates were finally apparently relieved in September 2023.
The BIG question: Were the gates completely repaired? Was the dam refilled again? Did the gates jam again? Did the damage on the sides of the gorge from 2023 give way? What is left of the dam today?
The only way such damage could happen to Malana-I is IF there was massive discharge from upstream.
The question to further ask now is what is the condition of the Malana Glacier? Did the cloudburst trigger a glacial slip or burst? Remember Kedarnath 2013?
With two incidents in back to back years + history of similar incidents in the last decade - across the himalayas, its now clear that changing rainfall patterns in the himalayas has rendered flood data of small hydro projects in upstream areas useless. Are we going to wake up and adapt? Are we going to pause and relook any projects under construction?
Story of Malana Valley in Himachal Pradesh on the night of July 31-Aug 1, 2024.
(See post thread for images to help understand)
In a tragic replay of what happened in the Teesta River Valley in Sikkim in 2023, two hydro power projects have mostly been totally destroyed in the Malana rivulet valley on the night of July 31-Aug 1, 2024.
A total of 186 MW of power generation capacity and hundreds of crores of investment is probably gone.
All images and videos I have come across are of the storage unit of the Malana-I power project. Malana-II is apparently still inaccessible and there is no news of the situation there. Looking at the damages in the valley, it is highly unlikely that Malana-II has escaped unscathed.
The Malana rivulet originates from the Malana Glacier in the Beas basin in Himachal Pradesh. It flows quite rapidly downstream passing below the famous village of Malana to meet the Parvati River at Jhari. The Parvati then meets the Beas at Bhuntar.
Malana rivulet has two power projects built on it.
Malana-I - 86 MW and Malana-II - 100 MW. Malana-I is older than Malana-II.
Malana-II is upstream of Malana village and Malana-I downstream. Both the projects 'touch' each other. Malana-II ends just a few metres from where Malana-I begins. Malana-II was built because it was felt that the rivulet had potential to generate more energy.
Both the dams are technically 'run of the river' but have differing designs. Malana-II has bigger pondage than Malana-I. Interestingly, Malana-I has its powerstation on the banks of the Parvati River as its tunnel geometry brings it to the Parvati gorge. Malana-II's power station tucked behind the barrage of Malana-I, is not very visible in satellite pictures as the gorge is quite narrow.
Both the dams have had a troubled history - as is the case with all himalayan hydel projects.
Malana-I - has had very publicised issues with the foundation of its above-ground reservoir. the design of this project has water from the barrage flowing into de-silting ponds and then into an above-ground reservoir before entering the intake for the Head Race Tunnel. The above-ground reservoir is basically a concrete tank built in the bed of the rivulet - like a large swimming pool. The foundation of this tank has failed multiple times since 2001. It has leaked water and has been repaired many times.
Yesterday the de-silting ponds and the reservoir have been completely destroyed. You can hear in one of the disaster videos a person yelling dam has burst, he is speaking about this dam.
The barrage of Malana-I has a peak flood discharge capacity of 600 cumecs. It looks like it was overwhelmed completely for the ponds and reservoir to be destroyed. Malana-II upstream has flood discharge of 650 cumecs, just 50 higher than Malana-I. 50 cumecs will not cause damage like this, thus there was massive flow from upstream.
Malana-II - has had an equally troubled history and as recently as the cloudburst in the same rivulet in July 2023! Malana-II is a much bigger gravity storage pondage. Its floodgates jammed due to debris in 2023. It almost suffered an overtopping. Breaches were observed at the top of the dam. Lucky, it held. The jammed gates were finally apparently relieved in September 2023.
The BIG question: Were the gates completely repaired? Was the dam refilled again? Did the gates jam again? Did the damage on the sides of the gorge from 2023 give way? What is left of the dam today?
The only way such damage could happen to Malana-I is IF there was massive discharge from upstream.
The question to further ask now is what is the condition of the Malana Glacier? Did the cloudburst trigger a glacial slip or burst? Remember Kedarnath 2013?
With two incidents in back to back years + history of similar incidents in the last decade - across the himalayas, its now clear that changing rainfall patterns in the himalayas has rendered flood data of small hydro projects in upstream areas useless. Are we going to wake up and adapt? Are we going to pause and relook any projects under construction?
Malana-I hydro power project.
Image 1: Power station on the banks of the Parvati River.
Image 2: Barrage site with de-silting ponds and above-ground reservoir visible.
(the power station for Malana-II is tucked in the shadow area of Image 2)
Image 1: Power station on the banks of the Parvati River.
Image 2: Barrage site with de-silting ponds and above-ground reservoir visible.
(the power station for Malana-II is tucked in the shadow area of Image 2)
Malana-II hydro power project
Image 1: Barrage site upstream of Malana village. You can clearly see its quite big.
Image 2: Schematic of the project
Image 3: Map from DPR of the project
Image 1: Barrage site upstream of Malana village. You can clearly see its quite big.
Image 2: Schematic of the project
Image 3: Map from DPR of the project
Image showing overtopping of Malana-II during July 2023 cloudburst with damage visible on the walls of the gorge.
News reports of the same:
tribuneindia.com/news/himachal/…
timesofindia.indiatimes.com/city/shimla/mo…
News reports of the same:
tribuneindia.com/news/himachal/…
timesofindia.indiatimes.com/city/shimla/mo…
A video showing the scale of the flood in the Malana Valley. Note the height of the slides.
https://x.com/sidhshuk/status/1819119548970455525
Damage at Malana-I barrage site. Note the narrator saying that movement ahead of this is possible only by helicopter.
https://x.com/sidhshuk/status/1819294480543207847
Shaky hard to follow video. But it shows the devastation of the reservoir and de-silting ponds of Malana-I
https://x.com/sidhshuk/status/1819044843957706985
Damage to barrage and storage structures of Malana-I as seen from an upstream view.
You can get a sense of the sheer volume of water that has forced its way through here!
You can get a sense of the sheer volume of water that has forced its way through here!
https://x.com/sidhshuk/status/1818886449497809163
The more I look at videos of the debris and flow in the Malana Valley, the more I am convinced that Malana-II dam has completely failed structurally. There is no other way for such debris to form.
https://x.com/kalapian_/status/1819344295713034699?t=kCeNm4igjSsx2hjovSHMJw&s=19
A very curious fact is emerging. I must check numbers but it appears the water storage capacity of Malana-II is higher than Malana-I.
Why is that a problem?
Usually you have a bigger storage downstream rather than upstream. Because if a dam upstream fails, you want the downstream dam to catch the water and protect property and lives.
Also Malana-II & Malana-I are very closely matched in flood discharge - 650 cumecs and 600 cumecs. In fact Malana-I which is downstream has lower discharge.
So already it's constrained if Malana-II does a full discharge. OR does Malana-II hold back discharge at 600 cumecs to protect Malana-I? That puts Malana-II at risk of failure due to overtopping.
It seems like very very poor planning for disaster at this point. And I wonder how alarm bells did not ring at the Central Water Commission when Malana-II almost fell apart in July 2023!
Why is that a problem?
Usually you have a bigger storage downstream rather than upstream. Because if a dam upstream fails, you want the downstream dam to catch the water and protect property and lives.
Also Malana-II & Malana-I are very closely matched in flood discharge - 650 cumecs and 600 cumecs. In fact Malana-I which is downstream has lower discharge.
So already it's constrained if Malana-II does a full discharge. OR does Malana-II hold back discharge at 600 cumecs to protect Malana-I? That puts Malana-II at risk of failure due to overtopping.
It seems like very very poor planning for disaster at this point. And I wonder how alarm bells did not ring at the Central Water Commission when Malana-II almost fell apart in July 2023!
I am reading a lot about raised beds of rivers and streams after the July 2023 flashfloods being a major cause of floods in Himachal Pradesh in 2024.
Yes. It's possible.
If the bed of the streams and rivers have not been cleared of debris and water channels deepened again, a new flashflood will carry more debris.
It's a downright mess.
Opens up another angle to investigate in the Malana Valley...
Malana-II dam: was the dam operator able to do routine silt flushing operations after the 2023 flash floods? I am reading that till winter 2023 they had difficulty getting heavy earth moving equipment up there to excavate debris from the reservoir. If debris was not removed and silt flushing has not happened, storage of the dam would have been far lesser, making it's operations difficult and endangering the downstream dam.
Malana-I - after 2023 was the river bed examined? Was it raised? Was the foundation of the above-ground reservoir damaged? If it was not examined or damaged, why was it filled for operating?
Many unanswered questions.
Yes. It's possible.
If the bed of the streams and rivers have not been cleared of debris and water channels deepened again, a new flashflood will carry more debris.
It's a downright mess.
Opens up another angle to investigate in the Malana Valley...
Malana-II dam: was the dam operator able to do routine silt flushing operations after the 2023 flash floods? I am reading that till winter 2023 they had difficulty getting heavy earth moving equipment up there to excavate debris from the reservoir. If debris was not removed and silt flushing has not happened, storage of the dam would have been far lesser, making it's operations difficult and endangering the downstream dam.
Malana-I - after 2023 was the river bed examined? Was it raised? Was the foundation of the above-ground reservoir damaged? If it was not examined or damaged, why was it filled for operating?
Many unanswered questions.
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