The 275 MW Kopili Dam Power House of NEEPCO (North Eastern Electric Power Corporation Limited, a Union Ministry of Power Underaking) in Assam suffered major disaster on Oct 7, 2019. The penstock pipe that takes water from the Umrangso dam to the hydropower house burst during early hours in Assam’s Dima Hasao (earlier called North Cachar Hill) district, and massive quantity of water erupted, a lot of it entered the power house, where four employees of NEEPCO are feared to have been trapped/ washed away[i]. A large portion of the Kopili Hydro Electric Plant was also inundated and a temporary bridge was also washed away[ii]. Some videos of the situation are also available.[iii]
Even as the world remembers one of the worst dam disasters that happened on Oct 9, 1963[iv], at Vajont dam in Italy, killing at least 2000 people, we have another dam related disaster in India.
Information so far Unfortunately, there is no information either from NEEPCO[v] or Union Power Ministry or any other agency of Union Govt[vi] or Assam Disaster Management Authority[vii] about this disaster so far, so we have to depend on media reports.
The media reports[viii] say: “… a burst in a water tunnel at Umrangso early Monday morning (around 0430 am) that also led to massive flooding at the power project site and in other parts of the town… the water tunnel that carries water at 12000 litres/sec from the NEEPCO reservoir to the Kopili Hydro Power Project site led to massive flooding and a water fountain that rose up to several hundred feet into the sky. People said they heard a deafening sound and then saw the water sprout… The water tunnel that cracked was incidentally repaired last year”.
Another news report: “The NEEPCO authorities have sought help from the National Disaster Response Force (NDRF) and the Assam Rifles to deal with the situation. “The heavy force of the water flooded the entire area including the power house, triggering the crisis” Hemanta Deka, NEEPCO executive director (Operations and Management)” said.
After the incident, NEEPCO sent a letter to officials of seven districts downstream in Meghlaya and Assam Monday informing them about the damage to penstock (pipeline) of the Umrong reservoir (one of the two of the project) and said that as a safety measure to control the flow of water all gates of the reservoir are being opened.
Kopili HEP The Kopili Hydro Electric Project (HEP) has two dams, one on the Kopili River and one on its tributary Umrang stream. This project was developed by NEEPCO (Northeast Electric Power Corporation Ltd.). The first dam with 66 m height on the Kopli River is known as Khndong dam and the second one with 30 m height is known as Kopili dam located at Umrangso. Water from the Khandong reservoir is utilised in the Khandong power station through a 2852 m long tunnel to generate 50 MW (2 X 25 MW) of power. The tail water from this powerhouse is led to the Umrong reservoir. The water from Umrong reservoir is taken through a 5473 m long tunnel to the Kopili power station to generate 200 MW (4 X 50 MW) of power [Its possibly this tunnel that burst on Oct 7, 2019, leading to the disaster]. An additional 25 MW was added to the Khandong dam in the Stage two of the Kopili HEP, making the total power generation 275 MW. Both Khandong and Kopili dams are concrete gravity dams. The work on the project started in 1976, the first unit of this Kopili HEP was commissioned in March 1984. Additional unit under stage two was commissioned in July, 2004.
SANDRP, in a submission to the Expert Appraisal Committee (EAC) in Sept 2013 had raised a number of issues about the Kopili HEP while the EAC was considering clearance for the Lower Kopili HEP[ix], including the issue of corrosion of the parts of the Kopili HEP and issue of Safety.
In Sept 2015[x], NEEPCO move to increase the height of the Khandong (upstream) dam from 719 to 725 m raised a lot of questions.
The Kopili Power house has undergone “Premature” Renovation & Modernisation, completed in 2015-16[xi] at a cost of over Rs 132.5 crores. However, the penstock failure was one of the REMAINING issues after R&M, as can be seen from the slide of the NEEPCO CMD post R&M.
Lot of Questions, will we ever get answers? Media has quoted NEEPCO officials blaming the acidic water inflow from Meghalaya, but that is not a new development, its been known for decades. In spite of that, NEEPCO continues to operate the dam and the power station, taking all the inherence risks, without apparently having even a proper disaster management plan in place.
Secondly, As NEEPCO CMD’s presentation about “premature” R&M shows, most affected components due to acidic water included Penstocks, with a picture showing corrosion in penstocks.
“Issues remaining after R&M” includes “Penstock failures: Going for major replacement of all critical areas; Coating”.
If that was the case, why was this not taken up immediately, rather going for continued operation of the risky project?
Thirdly, while the penstock failure seems to have happened early in the morning, even till evening, why was NEEPCO not able to stop the water going into the penstocks from the dam? It was because of the failure of this water outlet control mechanism that the NDRF, ASDM and Assam Rifle persons could not reach the power house since water continued to flow out of the damaged penstock and into the power house. Why did they have to reduce the water storage by releasing water from the dam before they could reduce water flow to the penstock?
The penstock pipes and tunnels were in repaired last year as per NEEPCO statements in the media. If that was the case, who executed the repairs and who certified adequacy of such repairs?
These and many such questions are destined to remain unanswered going by the experience of past dam related disasters. Let us hope that is not repeated this time.
NEEPCO’s track record Incidentally, NEEPCO’s under construction Kameng dam has already known to have suffered several leakage issues at some four different locations[xii]. Similarly the operation of NEEPCO’s Doyang dam have raised a lot of issues related to dam induced floods[xiii]. In case of NEEPCO’s Ranganadi project, even Assam Chief Minister has in the past warned NEEPCO not to release water while downstream areas are facing floods, as it has done several times[xiv].
Considering this track record, the least that Assam, Meghalaya and Union Govt can ensure is to commission an independent (consisting of non government persons having known to have taken stand independent of the government position) enquiry and suspend the operations at the Kopili project till the necessary steps taken after the enquiry ensures that all necessary steps are in place to ensure safe operation of the project.
ANNEXURE: The Kopili River
Kopili is a south bank tributary of Brahmaputra which originates in the Borail range mountains in Meghalaya at an altitude of about 1600 m and has a total length of 290 km up to its confluence with Brahmaputra. Its basin is bound by the Jaintia Hills in the west and the South Cachar and Mikir Hills in the east. Kharkor, Myntriang, Dinar, Longsom, Amring, Umrong, Longku and Langkri are its major tributaries in its upper reaches.
After entering Assam the Kopili separates the Karbi Anglong district from the Dima Hasao North Cachar Hills district up to its confluence with Diyung River on its right at 135 km. After the confluence with Diyung, Kopili flows into the Nagaon district in a north-westerly direction. The Jamuna River with a catchment of 3960 km2 flows to the Kopili at Jamunamukh.
The river then flows in western direction, and further downstream, the Umkhen-Borapani River which rises in the Shillong plateau and drains an area of 2038 km2 joins Kopili at a distance of 254 km from the left. The Killing River, known as Umiam in its upper reaches draining an area of about 1445 km2, flows into Kopili from the left at about 280 km. The Kopili River finally flows to Kalang, a spill channel of Brahmaputra, near Hatimukh after traversing a distance of 290 km2. The total catchment of Kopili River is about 16,421 km2.
1. Oct 10, 2019: Deccan Herald reported that the four missing persons still could not be traced and the fountain of water from the burst pipeline continued. BBMB and NHPC experts have been called to help. Shockingly, the NEEPCO CMD Vinod Kumar Singh was quoted as saying that it was accident and denied charges of negligence. https://www.deccanherald.com/national/east-and-northeast/bhakra-dam-experts-at-assam-hydel-project-mishap-site-767207.html
2. A NEEPCO spokesman on Wednesday said that the penstock (pipe) carrying water from the tunnel to the power house burst around 4.30 am on October 7 and in the process the isolating valve, meant to stop the water flow also got damaged, leading to the tragedy. Opposition congress blamed the centre for tragedy. The centre government did not release Rs 200 crore meant for maintenance of the plant in 2014. “Major repairing of the project was due in 2014. The pipeline expired its life span in 2014. However, it could not be done as the BJP led NDA government had not released the amount approved by the UPA government,” said Senior Spokesman of the Assam Pradesh Congress Committee, Durga Das Boro.
3. The ruptured water pipeline that washed away four people engaged in central Assam’s Kopili hydroelectric project on October 7 was repaired a year ago, raising questions about the quality of the work. “We are trying out best to check the inflow of water and sort things out within a day or two so that the powerhouse is approachable. This is not a normal situation and it is difficult to assess the damage until and unless we start restoring the system,” project manager Debotosh Bhattacharjee said. A project technician, declining to be quoted, said that they have been struggling to block the intake point of the penstock pipe that burst. The pipe had been carrying water from the NEEPCO reservoir to the Kopili powerhouse at 12,000 litres per second. Himanshu Thakkar of the South Asia Network on Dams, Rivers and People quoted a NEEPCO statement that said the penstock pipes and tunnels at Kopili were repaired a year ago. “If that was the case, who executed the repairs and who certified the adequacy of such repairs? These and many such questions are destined to remain unanswered going by the experience of past dam-related disasters,” he said.
4. Oct 11, 2019: No change in situation. Bhakra experts have arrived at the site. But 100 ft high water fountain continues to flow. No access to power house. NEEPCO officials are not able to stop water flowing through the broken penstock, which is also inundating the power house and surrounding areas.
5. Oct 12, 2019: Assam Chief Minister has instituted an inquiry. DIG South Assam Division P.K. Dutta has been asked to carry out the inquiry. Sonowal asked Minister in charge of Hill Areas Development, Mines and Minerals Sum Ronghang to visit the accident site with a high-powered team to take stock of the situation. The situation at the site remained same till Oct 11 evening, with water still flowing out and power house remaining inaccessible.
6. Oct 13, 2019: There is no change in situation as water flow and pressure has not reduced and no rescue effort could be started. NEEPCO independent director blamed acidic water due to Meghalaya coal mining, but that has been known for decades, as he himself says. Why was the project allowed to continue operations in spite of the risks?
7. Oct 14, 2019: A high-powered team of the Assam government on Sunday (Oct 13, 2019) inspected the pipeline burst site of NEEPCO’s 275 MW hydro-electric project at Umrangso in Assam’s Dima Hasao district.
8. Oct 15, 2019 Sources said loose earth in the basement of a two-storey pump house of the project is causing hindrance and it might take more time to recover the trapped persons. The earth blocking the entrance of the pump house has been cleared and excavators put into service to dig out the mud inside. Assam Hills Minister Sum Ronghang said the state government should order an independent inquiry by a team of experts to bring out the truth behind the rupture in the pipeline. Local residents said Neepco should stop blaming the coal mining authorities for the disaster.
9. Oct 16, 2019 There wass no trace on Monday of the four employees of NEEPCO who were feared to have been trapped inside a pump house of Kopili Hydro Electric Plant in Assam’s Dima Hasao district since its pipleine burst eight days ago. The flood not only submerged several office buildings, but also damaged more than 90 per cent of the machineries of the project, besides washing away the approach bridge of the plant. Massive pressure in the tunnel created a water fountain rising up to several hundred feet into the sky.
NEEPCO CMD VK Singh on Tuesday said that properties worth Rs 600 crore (approx) have been damaged in the tragedy.
10. Oct 17, 2019 Ten days after a pipeline at Kopili Hydro Electric Plant in Assam’s Dima Hasao district burst, flooding vast stretches of the project, four employees of the plant are yet to be located, officials said on Wednesday (Oct 16, 2019). Dima Hasao SP Sreejith T said that the four missing employees are yet to be located. “It is expected to take a few more days,” he said. NEEPCO general manager and head of Kopili Hydro Electric Project, Debotosh Bhattacharjee, said, “We are trying to open approaches to the underground sections where the employees are trapped. The sludge left after the waterlogging is causing obstacles in reaching the location.”