Nepal earthquake and the danger of building large dams in the seismically unstable Himalayas

Upper Tamakoshi HEP under construction: It was damaged in the earthquake. Photo Photo from company website
Upper Tamakoshi HEP under construction: It was damaged in the earthquake. Photo Photo from company website

By Himanshu Thakkar*

Experts have been warning about the danger of building large dams in the seismically unstable Himalayas, where the collapse of large infrastructure can magnify devastation in mountains. Such role of the projects in Uttarakhand flood disaster in June 2013 was confirmed by the Expert Body (chaired by Dr Ravi Chopra) appointed by the Union Ministry of Environment and Forests (MoEF), Government of India, following the Supreme Court order of Aug 2013 and also as per the affidavit of the MoEF in the Supreme Court in December 2014.

The huge earthquake caused in Nepal serious damage to the 111 MW Rasuwagadhi Hydropower station, which a Chinese company started to build two years ago, 67 kilometers west of the quake’s epicenter in Rasuwa district of Central Development Region. The Rasuwagadhi Dam was being built on the upper Trishuli River in a very remote corner of Nepal near the Tibetan border. The dam’s reservoir is to stretch back 25 km, holding back 1500 million cubic metres of water. Writer Michael Buckley asks in his article in “The Ecologist”: “Rasuwagadhi Dam was described as severely damaged by the quake. And that brings up a nightmare scenario. What if that dam were up and running, with a huge reservoir sitting behind it? … It would be a Fukushima moment – earthquake followed by tsunami.”

In a news report that appeared eight days after the earthquake, Ganesh Neupane, chief of the environment division of the Upper Tamakoshi Hydropower Company Limited, said, “Some 200 Chinese technicians and engineers as well as 70 Nepalese workers are stranded in the powerhouse station at the hydropower project site after a massive landslide caused by the earthquake blocked the 11-kilometer-long Lamabagar-Gongar stretch of the road connecting the region. The 456 MW Project of Nepal Electricity Authority is located at Lamabagar VDC, Dolakha District, Janakpur Zone, Central Development Region. The workers are stuck but safe at the Upper Tamakoshi hydropower project in Lamabagar Area in Dolakha district, where reports suggest that more than 90 per cent of houses in rural areas have been destroyed. The stranded workers are from China’s Sinohydro Corporation Limited, the contractor of civil construction work for the Upper Tamakoshi Hydropower Company Limited in charge of the project.”

Our colleague Ratan Bhandari reported on May 4, 2015 that Nepal’s only storage dam, the Kulekhani Reservoir dam has cracked by the earthquake. According to Nagarik daily (Nepali) the water level in the 114 m high Kulekhani dam is being reduced by three meters. Nepal Electricity Authority is doing micro study of the dam. According to the senior officer of NEA, the dam is cracked in various part from north to south.

“Hydroworld”, an industry trade magazine, reported that the 144-megawatt Kaligandaki hydroelectric power station and 22.1-megawatt Chilime hydropower plant “may have been affected according to news reports from the area.” Kaligandaki on the Gandaki River is about 187 miles west of Kathmandu near Mirmi in the district of Syangja District. Chilime Project on the Bhotekoshi river is in the district of Rasuwa, which is 83 miles north of Kathmandu. In Aug 2014, Nepal’s deadliest landslide in a decade caused destruction that knocked out 10% of its power generation capacity.

It is clear from above how the hydropower projects were damaged during the earthquake and they in turn can be cause for deaths and damages. Post-earthquake, as a prominent hydro-world site  noted, that the future of Nepal’s hydropower development will inevitably now demand significantly greater attention to structural integrity in the face of seismic events. As Martin Wieland, Chairman of the ICOLD Committee on Seismic Aspects of Dam Design, concluded in his 2012 paper, dams are not inherently safe against earthquakes.

The Zipingpu Dam in Sichuan Province in China has been implicated in the disastrous quake of 2008 that killed over 85,000 people and left millions homeless. The dam was just four miles from the epicentre of the 7.9-magnitude quake. The quake cracked Zipingpu Dam and caused damage to 60 other smaller dams in the region. Dam personnel and miliary rushed to empty water from scores of dam reservoirs, causing considerable flooding downstream.

Japan is known to have gained expertise in dealing with earthquakes. However, what happened in that country on March 11, 2011, started with a magnitude 9.0 earthquake, compounded first by tsunami and then by melting of three nuclear reactions, the after effects of that disaster are still being experienced not only by Japan, but even by the nuclear industry across the world. This was a case of cascading disasters.

India is prone to such cascading disasters in several ways. Nepal experienced some such events after the April 25 earthquake. One instance of this was the landslides that killed large number of people, these landslides were second order disaster after the earthquake. Another such instance would be if a major dam or hydropower project, while still full of water, were to get damaged after the earthquake or a landslide. David Petley and EWF have indicated a third possibility when a landslide post earthquake was to create a dam on river, which would then be a bomb for the downstream areas when it inevitably bursts.

Geologists and environmentalists have said if a Nepal-like earthquake strikes any of the Himalayan states including North East India and Bhutan, there will be a large scale destruction and death owing to compounding of disasters due to hydropower projects. Dr SP Sati from the department of Geology, HNB Garhwal University, Srinagar, said about Uttarakhand hydro, “Barring Tehri Dam, which is rock and mud-filled structure, most of the hydropower dams in Uttarakhand are made up of reinforced concrete cement. The ability of these dams to withstand high-intensity tremors is highly questionable. They could collapse and lead to a large scale death and destruction downstream.” Tehri dam is also yet to be tested, considering the large number of landslides that have already occurred in its catchments.

The possibility of compounding or cascading disasters is further compounded by some additional reasons. First is the climate change. As it was apparent in Uttarakhand flood disaster of June 2013, while the unseasonal rainfall was the primary reason, the Kedarnath shrine and downstream Mandakini and Alaknanda and Ganga rivers faced bigger floods due to the glacier lake outburst flood. Another compounding factor in that case was the massive silt dumped on the riverbed by the under construction hydropower projects.

This factor of under construction and operating hydropower projects adding several layers (e.g. deforestation, blasting, tunneling, minding, muck dumping, damming, to name only a few) to the cascade of disasters is something that is not even acknowledged, leave aside assessed or factored in decision making process.

It is high time we wake up to these clear dangers staring at us. However, the Union Ministry of Environment & Forests is busy diluting environmental governance in India. Just a day before the April 25 earthquake, the Expert Appraisal Committee on River Valley Projects was sitting to consider the massive 6000 MW Pancheshwar Dam on Mahakali river on Nepal-Uttarakhand border. SANDRP, MATU, Toxics Alliance, Himal Prakriti, Dr Bharat Jhunjhunwala and a number of other groups & individuals have written to the EAC why this project should not be given even first stage (terms of reference) clearance. But the way Indian Prime Minister Narendra Modi and the Nepal government signed the agreement when Indian PM visited Nepal last year, it seems difficult to believe that wiser counsel will prevail. In fact, the current government is pushing more hydropower projects in Uttarakhand, some like massive Lakhwar Dam on Yamuna without so much as Environment Impact Assessment and public consultations.

*With South Asia Network on Dams, Rivers and People (SANDRP). Contact: ht.sandrp@gmail.com. These are excerpts from a comprehensive article on the earthquake and its impact on the ecology by Thakkar in https://sandrp.wordpress.com. For full article click HERE

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