3 glacial lakes in Tibet could deluge parts of central Nepal


KATHMANDU, March 6: A new study has revealed that three glacial lakes in Tibet are in very critical condition, posing serious threats to people living downstream on the banks of the Bhotekoshi River.

The study, jointly carried out by the Central Department of Geography at the Tribhuvan University (TU) and the Asian International River Center at the Yunnan University of China, has concluded that You-Mo-Jian-Co, Qui-Ze-La-Co and Jia-Long-Co glacial lakes, which are located within the watershed area of the Bhotekoshi River, are highly vulnerable.

“If these lakes burst out, severe impacts could be felt along the Bhotekoshi River, particularly between Tatopani and Dolalghat areas on the Araniko highway,” said Narendra Raj Khanal, a professor at the TU´s Central Department of Geography. According to Khanal, who was the team leader for the one-year-long study, there are several other potentially dangerous glacial lakes in the Bhotekoshi River´s watershed area but three could possibly burst out in future.

“These three glacial lakes in the Tibetan region require constant monitoring and immediate mitigation,” said Khanal. “Our government should also be constantly monitoring these lakes, considering the threats that the Nepali people face.” Khanal also stressed the need for setting up of effective early warning systems to protect human lives in events of Glacial Lake Outburst Flood (GLOF) in Tibet.

The finding of this new study, the final report of which is yet to be published, implies that the risk of GLOF in Nepal is higher than what is generally assumed. In Nepal, understanding of GLOF has been largely shaped by scientific studies carried out by the International Center for Integrated Mountain Development (ICIMOD). A 2011 report by the ICIMOD states that Nepal has 21 potentially dangerous lakes – six of which need immediate mitigation measures.

“In our new study, we have tried to see the risk of GLOF in Nepal beyond the northern border,” said Khanal, who was also a member of the team that prepared the ICIMOD´s report on Nepal´s glacial lakes. “We cannot ignore possibilities of GLOF in the Tibetan region.”

Experts also stress the need for mitigating the risk of GLOF in four glacial lakes of Nepal, which the ICIMOD report says are as critical as Tsho Rolpa and Imja. Currently, mitigation measures, like lowering water level of glacial lakes, have been taken only in Tsho Rolpa and Imja. Such measures have not been initiated as yet in other equally vulnerable lakes like Lower Barun, Lumding, West Chamjang and Thulagi.

“These four glacial lakes also need immediate mitigation measures,” said Pradeep Mool, Coordinator of Cryosphere Initiative at the ICIMOD. “But, mitigation measures are very costly. Millions of dollars are required just for transporting equipment to glacial lake areas. So, cost-benefit analysis is done before starting such initiatives. Imja was chosen over other lakes for mitigation measures, considering tourist destinations downstream.”

Published on 2014-03-06 00:00:00

Water volume of Imja lake doubles in three years



KATHMANDU, Oct 9: In yet another sign that exposes vulnerability of Imja Tsho, one of Nepal´s highly dangerous glacial lakes, a new study has revealed that the lake´s water volume has nearly doubled over the last three years.

The new study, conducted by the High Mountains Adaptation Partnership (HiMAP), coordinated by the University of Texas and The Mountains Institute (TMI) with support from the USAID, reveals that Imja Tsho now contains over 60 million cubic meter water — almost double the lake´s previously-stated water volume.

In 2009, a study by the International Center for Integrated Mountain Development (ICIMOD) had stated that Imja Tsho, which glaciologists say was formed just half a century ago, contained about 35 million cubic meter water.

Contrary to what the ICIMOD report-2009 stated, the HiMAP study, conducted in September last year, says that the volume of water in Imja Tsho has increased alarmingly by 2012. The finding of the study was revealed for the first time at the inception workshop of Community Based Flood and Glacial Lake Outburst Risk Reduction Project (CFGORRP), an initiative taken to deal with the impact of climate change in the Khumbu region, on Wednesday in Kathmandu.

“Our study only reasserts the fact that Imja Lake is getting more vulnerable,” said Marcelo Somos-Valenzuela, a PhD candidate at the University of Texas, who was involved in mathematical calculation for finding out the lake´s water volume. “The increase of water volume in Imja Lake can be related to the rise in temperature in high mountain ecosystems.”

National Project Manager of the CFGORRF Top Bahadur Khatri says it is too early to conclude whether the finding of the HiMAP study is absolutely correct. “Other findings should validate what the HiMAP study states,” said Khatri. “But, we have no doubt that the lake´s size and water volume are both increasing constantly.”

According to the HiMAP study, the calculated volume of water that could get discharged from Imja Lake in case of a Glacial Lake Outburst Flood (GLOF) has also increased to 34 million cubic meters. Earlier, the GLOF water was calculated to be just around 20 million cubic meters.

Assessing the risk of potential GLOF events in the Khumbu region, government authorities are now accelerating efforts to lower Imja Lake´s water level by at least three meters under the CFGORRF. After Tsho Rolpa, this is the first time that a glacial lake´s water level is likely to be lowered in Nepal. Earlier in 2000, Tsho Rolpa´s water level was lowered by three meters.

Asked whether lowering of Imja Lake´s water level by three meters, especially in view of the HiMAP study´s new finding, is sufficient to avert GLOF events in the Khumbu region, glaciologist Dr Rijan Bhakta Kayastha said, “Reduction of Imja Lake´s water level by three meters is good enough for now.”

According to Dr Shrestha, an associate professor at the Kathmandu University (KU), the height of Imja Lake´s end moraine is just 30 meters, nearly 100 meter lesser than that of Tsho Rolpa. “Thanks to its low end moraine, lowering of water level by three meters is adequate for now despite the increase in the water level,” he explained.

More than 30,000 people could be affected if Imja Lake, located at an altitude of 5,000 meters just above Namche bazaar in Solukhumbu district, bursts, according to experts. The lake, surface area of which was just 0.03 square kilometers in 1960, has already developed into a 1.01 square kilometer lake.

As part of the CFGORRF, funded by the Least Developed Countries (LDC) fund of the Global Environment Facility (GEF), early-warning system will also be developed in the Khumbu region. “We will follow best practices of Tsho Rolpa while lowering Imja Lake and developing early warning system in the Khumbu region,” said Khatri.

Published on 2013-10-10 00:35:37

Lowering Imja alone will not prevent GLOFs, say experts


KATHMANDU, Sept 22: A month ago, Keshav Raj Sharma, a hydrologist at the Department of Hydrology and Meteorology (DoHM), was about to sleep. His cell phone started buzzing. It was from an unknown number.

“Sir, are you sleeping?” said the caller, who introduced himself as a Dolakha-based journalist. “Tsho Rolpa Lake has just burst out; thousands of people are going to die. You must do something to save us, sir.”

Petrified by the potential devastation that Tsho Rolpa outburst might cause, Sharma restrained his fears; and just said, “Don´t worry; nothing is going to happen.”

As soon as he hung up the phone, Sharma contacted the field office, which was set up by the DoHM to monitor glacier activities in Tsho Rolpa. The field office dismissed rumors about Tsho Rolpa outburst. “Only then was I relieved,” says Sharma, recalling the night of August 15.

Although the news of Tsho Rolpa outburst proved to be a flash flood in the Tamakoshi River, the risk of Nepal´s most vulnerable glacial lake bursting and causing catastrophic devastation in the downstream valley still looms large. Om Ratna Bajracharya, former Director General of DoHM, believes Tsho Rola is still Nepal´s most dangerous glacial lake. “The risk from Tsho Rolpa is still higher than from any other glacial lake,” says Bajracharya. “It is getting bigger and bigger every year.”

In 2000, in a bid to avert the risk of a Glacial Lake Outburst Flood (GLOF) in the Tamakoshi River basin, the water level in Tsho Rolpa was lowered by three meters through a 70-meter-long canal, which has been channeled into the Rolwaling River.

“That was just a temporary measure,” says Bajracharya. “Unless we lower the water level in Tsho Rolpa by 17 meters, as suggested by a study report in the 1990s, safety of thousands of people living on the banks of the Tamakoshi river basin cannot be ensured.”

According to Kamal Budhathoki, former Deputy Director General (DDG) of DoHM, even if water level in Tsho Rolpa is lowered by just nine meters, the risk of GLOFs in the Tamakoshi River basin can be reduced to a great extent. “There is another report prepared by an American glaciologist in collaboration with DoHM experts. The report says lowering of water level in Tsho Rolpa by about 12 meters is sufficient,” says he.

However, instead of further lowering Tsho Rolpa, government authorities, under a US$ 7.2 million project funded by the Least Developed Countries Fund (LDCF) of Global Environment Facility (GEF), are now working toward reducing the water level in Imja, another dangerous glacial lake in the Khumbu region, some 163 km from Kathmandu.

Some experts argue that Tsho Rolpa is situated at a relatively low altitude, which makes it more vulnerable than other high-altitude glacial lakes, including Imja. “The lower the altitude, the higher the risk of GLOF events,” explains Bajracharya. “Impact of global warming can be felt more in low-altitude glacial lakes.”

Going by what Bajracharya argues, Tsho Rolpa, situated at an altitude of around 4,500 meters, is more vulnerable to the effects of global warming. At an altitude of over 5,000 meters, glaciers that feed Imja are less exposed to rising temperature.

An expert, unwilling to be named, says Imja was chosen just because it caught the attention of national and international mountaineers. “Imja is in close proximity to climbing and trekking routes in the Khumbu region. Therefore, many people see melting glaciers there,” says he. “But, there are other glacial lakes that are more vulnerable. But, very few have noticed them.”

According to a 2009 report by the International Center for Integrated Mountain Development (ICIMOD), apart from Tsho Rolpa and Imja, there are four more glacial lakes which are at the risk of GLOFs. These lakes include Thulagi, Lumding, Lower Barun and West Chamjong. Apart from gradual degradation of moraines, fast receding of glaciers has also rendered these lakes vulnerable.

Since 1964, at least 10 GlOF events have been recorded in Nepal. As the Himalayas face threats from rising temperature, minimizing the risk of GLOFs by lowering water levels, developing early-warning system in the downstream human settlements and empowering local communities to adapt to climate change seems necessary, say experts.

After Tsho Rolpa, Imja Lake will be lowered by three meters


KATHMANDU, Sept 20: Fearing massive destruction from a potential Glacial Lake Outburst Flood (GLOF) in the Khumbu region, government authorities, assisted by a United Nations agency, are now accelerating efforts to lower the water level in Imja glacial lake by three meters.

This is the second time that water level of a glacial lake is being lowered in Nepal — more than a decade after the volume of water in Tsho Rolpa, risk of outburst of which led to a hue and cry among the local people in the late 1990s, was reduced. In 2000, water level of Tsho Rolpa was reduced by three meters through a 70-meter-long water canal, which has been channeled into the Rolwaling River.

After signing an agreement with the United Nationals Development Program (UNDP) in July this year, the Department of Hydrology and Meteorology (DoHM) has now begun a feasibility study to lower the water level of Imja, located at the altitude of 5,000 meters in the Khumbu region, about 160 km from Kathmandu.

As in Tsho Rolpa, water level of Imja, which could possibly affect thousands of people in Solukhumbu district in the event of a GLOF, will be lowered through a water canal. The 70-meter-long canal will be channeled into Imja khola, which originates from Imja Lake itself and gets bigger and wider after receiving glacier melting from other mountains, including Ama Dablam.

The feasibility study for reducing water volume in Imja will be followed by preparation of a detailed engineering design, which will decide what type of canal would be the most cost-effective. “If everything unfolds as planned, Imja Lake will be lowered by 2017,” said Rajendra Sharma, Senior Divisional Hydrologist at the DoHM. “Water level lowering will reduce the risk of a GLOF in Imja Lake.”

Lowering of water level in Imja is a part of a US$ 7.2 million project, funded by the Least Developed Countries Fund (LDCF) of the Global Environment Facility. As part of the project, which will run until 2017 from 2013, early warning system will be developed in four districts in the Tarai — Siraha, Saptari, Udayapur and Mahottari — to protect people and their properties from GLOFs and flash floods in the future.

Experts say Imja Lake, which is believed to have been formed just about half a century ago, is vulnerable due to rapid expansion of its area combined with degradation of its moraine dam. According to a 2009 report prepared by the International Center for Integrated Mountain Development (ICIMOD), Imja has developed into a 1.01 square kilometer lake over the last 50 years. In 1956-1963, according to the same report, Imja was just a 0.03 square kilometer lake.

“The rate at which Imja Lake has been expanding is alarming,” says Kamal Budhathoki, former Deputy Director General of the DoHM. “Along with the area, the depth and water storage capacity of the lake is also increasing, which has posed threats of imminent devastation.” Budhathoki says glacier around Imja is receding much faster, which has made reduction of water volume in this glacial lake a much-needed measure.

Kashmir could face disaster like Uttarakhand’s – experts

SRINAGAR, India (Thomson Reuters Foundation) – Devastating flooding in the northern Indian state of Uttarakhand in June, caused in part by the collapse of a glacier-fed lake, has raised worries in other Himalaya regions could be at risk of similar tragedies, experts say.

In southern Kashmir, in particular, a number of glacial lakes in the upper reaches of the famous tourist resort of Pahalgam could be vulnerable to collapse if the region faces extreme rainfall or earthquakes, scientists say.

“The Uttarakhand tragedy has rung alarm bells for the entire Himalayan belt, considering its fragile ecology and environment. Since we are the part of the same fragile Himalayan belt, any extreme meteorological event could create havoc here as well,” Mohammad Sultan, head of the department of geography and regional development at Kashmir University, told the Thomson Reuters Foundation.

More at:  http://www.trust.org/item/20130829092137-f17br

Early warning technology protects Nepali villagers from sudden floods

The Phulping bridge crosses the Bhote Koshi River in Jhirpu Phulpingkatti, a village near Nepal’s border with China. It replaced an old stone bridge, remnants of which can be seen to the left, which was washed away in the floods of 1981. THOMSON REUTERS FOUNDATION/Saleem Shaikh

Thomson Reuters Foundation – Wed, 22 May 2013 10:45 AM
Saleem Shaikh

JHIRPU PHULPINGKATTI, Nepal (Thomson Reuters Foundation) – For years, Deepa Newar and her neighbours lived with the fear that their livelihoods – and even their lives – might be swept away without warning.

Newar and her fellow residents of Jhirpu Phulpingkatti, a village some 112 km (70 miles) northeast of Kathmandu, Nepal’s capital, live perched on the bank of the Bhote Koshi River. The river is prone to sudden, devastating floods that can swamp fields, carry away livestock and even kill those who do not manage to flee to higher ground.

The 2.5 acres (1 hectare) of land on which Newar cultivates paddy rice and maize have suffered severe flooding four times in the last 32 years, most recently in 2011.

Looking at the swirling grey waters of the river that flows into Nepal across the border with China’s Tibet Autonomous Region, 10 km (6 miles) upstream, the 39-year-old recalls those disasters.

“(The river) left behind a trail of death and destruction whenever it has turned into a monster,” she says.

But Newar now enjoys a sense of safety for herself and her family, thanks to an early warning system for floods installed by the Bhote Koshi Power Company (BKPC) at its hydropower plant on the river.


Flash floods can be caused by severe storms or the failure of levees, but the Bhote Khosi River is also susceptible to glacial lake outburst floods. These result from the catastrophic failure of a natural dam high in the mountains that contains glacial meltwater. Such failures are becoming a greater risk as warming temperatures linked to climate change lead to faster glacial melt and greater volumes of water in the lakes.

The Bhote Khosi river basin covers an area of about 3,400 square km (1,300 square miles) and has an estimated 150 glaciers. Of its 139 glacial lakes, whose area totals some 16 square km (6 square miles), 59 are highly vulnerable to outbursts, according to a study conducted by the International Centre for Integrated Mountain Development (ICIMOD), an intergovernmental body of eight countries in the Hindu Kush-Himalaya region, including Nepal and China.

In 1981, a glacial lake outburst flood in the river basin washed away several bridges, including the China-Nepal Friendship Bridge along the Araniko Highway, said Pradeep K. Mool, a glaciologist at ICIMOD in Kathmandu.

Until 2010, floods could strike the villages with no warning. Residents had virtually no time to move to higher ground and were forced to leave behind their livestock and crops, suffering financial losses as well as emotional distress.

“Before the advent of the warning system … we were at risk of being washed away,” said Newar.

Janak Raj Pant, maintenance manager at the Bhote Koshi power plant, said that the river is subject to erratic flows, particularly during the monsoon. For this reason, the power company arranged for the early warning system to be installed in 2010 to benefit the downstream communities in Sindhupalchowk district.


The early warning system gives villagers 5-8 minutes’ notice of a flood – just enough time to save themselves.

Five flood sensors are positioned near the Nepal-China Friendship Bridge, about 6 km upstream from the power station.

If the water in the river reaches a dangerous level, the sensors activate sirens placed at four locations, including one at the power plant. The sirens warn the communities to flee to higher ground. Residents use their mobile phones to warn other villages further downstream.

According to Pant, a glacial lake outburst flood takes about five minutes to travel from the Nepal-China Friendship Bridge to the plant. He says lives can be saved if people respond to the alarm immediately.

“At present, the warning system can make the sirens blare five minutes before any flood can strike any of the 79 downstream villages of Sindhupalchowk district,” said Pant, standing beneath the red siren mounted on a side wall of the company’s building.

According to Pant, it is not currently possible to give more warning because information on flooding is not available from the Chinese side of the border.

About 40 percent of the Bhote Koshi river basin is in Nepal, with the remaining 60 percent in China.

Other residents of Jhirpu Phulpingkatti agree that the system has given them a sense of security, but they would like the lead time given by the alarm to be extended.

More sensors need to be placed further upstream within Nepal, especially at glacier snouts and where glacial lakes have formed or are forming, commented Joydeep Gupta, a New Delhi-based journalist and expert on South Asia river basins and flood warning systems.


The ICIMOD study shows that Nepal has experienced at least 24 glacial lake outburst floods. Of these, 14 are believed to have occurred in Nepal itself, and 10 were the result of flood surge overspills from the Chinese side of the border. According to data from the Nepal Meteorological Department, such floods occur on average once every three years in Nepal.

The glaciers in the Hindu Kush-Himalayas are retreating, which scientists believe is the result of climate warming. As glaciers melt, the water released into lakes can build pressure on the natural dams and increase the risk of an outburst flood.

“We have already sought proposals from interested firms to expand the warning system to other vulnerable districts (near) the Bhote Koshi River,” said Pant. “It is hoped that in coming months we should be able to install alarm systems in as many districts as possible.”

“(The) Nepali government should also replicate and establish such early warning systems at all streams to (avoid) or reduce loss of lives or damage,” said Gupta.

But priority should be given to the streams emanating from the unstable glacier lakes identified by ICIMOD in its recent study, he emphasised. According to Gupta, China, as the upstream country, should collaborate with Nepal to share information about flash floods or glacial lake outburst floods hours before they reach the Nepali border, to allow maximum time for warnings to vulnerable downstream communities.

“Any viable information-sharing system by which Chinese officials can pre-inform their Nepali counterparts of any risk of flash flood or (glacial lake outburst flood) would be very helpful. A similar system between China and India already saved many lives in a flash flood in the Sutlej river area a few years ago,” he said.

Saleem Shaikh is a climate change and development reporter based in Islamabad.

Weblink: http://www.trust.org/item/20130522093446-pfy20/