July 25, 2021

‘The colour is blue’: Strange changes to Mekong River as hydropower dams and climate change make their mark

13 min read

LUANG PRABANG, Laos: Before dawn, monks walk the streets of Luang Prabang collecting alms. The Mekong gently meanders in the darkness. The river is a peaceful but powerful force here.

A heavy mist hangs over the water long after the sun has risen. It is late morning before it burns away at this time of year, in the milder heat of winter. Life is generally slow in northern Laos, but the river always stirs, with a fisherman’s net or a boatman’s call. And it always flows, its natural rhythms for millenia shaping the land and its people.

But roles have now reversed. Now man holds reign. And there is something wrong with the Mekong. The ‘Mother of Water’ as this great river is known throughout the regions it passes, is sick. 

A fisherman stands in the cold mist descended on the Mekong River in the early morning, near Luang Prabang. (Photo: Jack Board)

As hydropower dam projects come online, at the same time as the effects of climate change start to manifest, the Mekong’s even flow has been disrupted. River levels are fast changing as water is stored and released. Dry and wet seasons have become confused. Fish breeding is irregular and passage has become problematic as water levels drop to record lows. 

The Mekong is defined by its colour – a deep ochre that reflects the life-giving sediment that feeds its fauna and enriches the soils that countless communities depend upon. At present, in parts, even that has changed.

With the region’s largest hydropower operation – the Xayaburi dam – now operating, another major project planned on the mainstream of the river in Laos within years, and others on the way in the Mekong’s tributaries, experts believe the river’s future has never been more at risk.

Peaceful, easy days on the Mekong may be under threat from increased development of the river as a commodity. (Photo: Jack Board)

“For the past year, the Mekong River’s ecosystem has been treated badly all the time. If we talk in boxing terms, it has faced a lot of jab punches, but the issue of clear water in the Mekong is the knockout,” said Montri Chantawong, who has spent 15 years studying the river and is currently researching health issues caused by changes in the river for public health agency, the ThaiHealth Promotion Foundation.

For many in Laos – and some neighbouring countries – hydropower has brought prosperity and potential. The country with ambitions to be the battery of Southeast Asia is seizing its most abundant resource and transforming the lives of its people, who have long been isolated and impoverished.

At the same time, the projects bring worries, because the knock-on environmental effects are being felt, hard and fast.

The Mekong provides livelihoods to millions of people throughout the Lower Basin region. (Photo: Jack Board)


Downstream from Luang Prabang, the Xayaburi dam began full operations last October. It is a strategic piece of infrastructure stretching across the expanse of the river, as controversial as it was ambitious to construct. Its output potential is 1285 megawatts, power that will be managed by Thailand’s electricity utility EGAT and exported across the border.

“My feeling for that project is that it’s quite impressive. I was involved from the very beginning,” said Dr Daovong Phonekeo, Permanent Secretary of Laos’ Ministry of Energy and Mines.

After close to a decade of construction, the dam’s opening ceremony late last year marked a major step in Laos’ hydropower strategy, one that has been promoted keenly by the government as a significant boost to state coffers and national economic development. The Mekong as a commodity has proven lucrative.

Nam Ou 1 is being constructed by a Chinese company on an important Mekong tributary. (Photo: Jack Board)

“The Laos government would like to promote the hydropower sector to be one of the characteristics of the economy, to be able to attract foreign investment and improve the economic situation,” Dr Daovong said.

“Back before 1995, very few households had access to electricity. But compared to the present, we have almost 94 per cent with access to electricity. They are able to make their life easier. They can buy a washing machine, freezer, refrigerator and other things to make their life more comfortable.”

However, the power produced by the Xayaburi and other major projects far exceeds energy demand in Laos. The race to generate profits in a power-hungry region are coming at the expense of the river’s sustainable health, according to environmental researchers and local residents. 

After just a few weeks of operations, as well as extensive testing periods, communities below the Xayaburi say the character of the river has changed. At Nong Khai in Thailand, the slow moving water makes for an unusual sight. It has even become a tourist spectacle in recent months.

Parts of the Mekong have suffered from record low water levels in recent months. (Photo: Jack Board)

“The river water has become clear and is without sediment. In some places, the water reflects the sky and looks blue. The colour is blue, like sea water,” Montri Chantawong said. “The villagers all say that they have never seen this before.”

The clearness and subsequent reflected colour of the river is believed by experts to be a symptom of very low water flow. The sediment carried naturally in the river is absent, likely leading to other side effects along the river.

“The fact is that clear water is water that is hungry for sediment. Therefore, erosion rates will be more severe on both the banks and in the water itself,” Montri said. Normally, the brown waters of the Mekong indicate a saturation of suspended sediments, which has less impact on the river’s banks. It is a problem that could spread as the river snakes its way towards Cambodia and the crucial Tonle Sap lake and finally into the Mekong Delta in southern Vietnam.

“The blue-green water phenomenon is likely to spread to other stretches of the Mekong River where low flows are encountered. The issues of low flows and sedimentation could possibly lead to adverse impacts that have been well-quantified,” said the Mekong River Commission Secretariat’s chief environment management officer, Dr So Nam.

But it is the inconsistencies that are making living on the banks of the Mekong more onerous. The one constant provider for people’s lives and wellbeing now cannot be trusted.

Montri Chantawong observes changes to the Mekong River from the Thailand’s Nong Khai. (Photo: Jack Board)


Boonme Dejsuthi has spent all of his 54 years in Nong Khai in Thailand. This past one has been the hardest. 

His view of the world has been an idyllic one from a lofty bank overlooking a gentle turn on the Mekong and his small fish farming operation has been a proud endeavour. 

Now, on the opposite bank of the river, the Laos side of the international border splitting the Mekong, hungry machinery is dredging sand from the shallows. The sharp hammering sound bouncing across the water is an emblematic soundtrack to the changes affecting the river. 

Vegetable growing has become more difficult on the less stable, less nutrient rich banks of the Mekong. (Photo: Jack Board)

Both Boonme’s fish farm operations and vegetable crop cultivation have suffered major losses in recent months. He blames the construction of the Xayaburi and the subsequent controlled water flow for the damage, with the last wipeout estimated to have cost him more than US$6500.

“Before the dam, the water currents and the time that the water came up and down were so natural. Now, they aren’t natural anymore. When the dam releases water, it comes very fast, knocking my fish out and ultimately killing them,” he said.

“Back then, farmers could plant vegetables down the riverbanks, but they can’t do that anymore because their vegetables will be flooded. We couldn’t see the riverbed but now, the water is so clear that I can see the riverbed through the net of my fishing basket. The light now shines directly to the fish. It’s a massive headache. 

“Maybe next time you come here, you won’t see me and my farm anymore. I don’t know if I can fight for so long.”

Boonme Dejsuthi has lost thousands of fish due to irregular river water level drops and rises. (Photo: Jack Board)

Further upstream in Ban Muang, the main river passage resembles an elaborate maze, where water cascades past sheer sand banks and rocky outcrops. Anuworrarat Chanai is an experienced boatman and well versed in navigating the Mekong’s idiosyncrasies. Even for him, the state of the river is strange.

“These days, it’s flooded in the dry season and the water drops in the rainy season. This is abnormal,” he said. 

Experts agree that while the impact of the Xayaburi on the lower Mekong basin is apparent, their lasting effects are still unknown. The Mekong River Commission (MRC), a body that coordinates with member state governments – Thailand, Vietnam, Cambodia and Laos – to manage the river and assess transboundary impacts of dam projects, says it is too early to criticise the project, despite finding that hydropower projects “pose adverse impacts to the river’s ecosystems, putting its sustainability at risk”.

Anuworrarat Chanai navigates the clear shallows in a section of the Mekong close to Ban Muang. (Photo: Jack Board)

“At this stage, it is rather too early to conclude. We need an operation record of at least a full-year and more from the dams to analyse,” the MRC Secretariat told CNA in a written statement.

But people like Anuworrarat are already exasperated. “This is because a group of people who think of their personal benefits, without looking and realising about others in their own country and environments in the area that will disappear,” he said.

“I want to see Xayaburi Dam as the last dam. I don’t want more dams on the Mekong River.”

With tentative future plans for nine more mainstream dams in Laos and a further two in Cambodia, it is unlikely that he will get his wish. The next piece of dam infrastructure is already being readied. What it will look like is already clear – it is a Xayaburi clone.

The clearness of the Mekong is troubling, environmentalists say, as it means crucial sediment is missing from the water flow. (Photo: Jack Board)


The golden Buddha images of the Pak Ou Caves are silhouettes in front of the rushing, muddy Mekong. Visitors gather here to take photographs and pay their respects. Some locals hope it will not be the only tourist attraction in the nearby vicinity in a few years.

About 30 kilometres north of Luang Prabang, the next mega project for the mainstream of the river in Laos is in its formative days, just a short boat journey further up from the popular caves. 

“If the dam is built, a lot of people will come to visit. There will be hotels. They can come stay. It will be fun,” a local boat driver said as he powered his vessel past yellow marker flags indicating the future site of the Luang Prabang dam.

Workers test the projected area before the commencement of construction of the Luang Prabang dam. (Photo: Jack Board)

This new dam is in a consultation process period, expected to be finalised by April. A technical review and preliminary assessment of the project is currently being undertaken by the MRC. These findings will lay down suggested guidelines, but do not need to be followed. 

The dam’s developers will be the same as its Xayaburi sibling but with a slightly increased power output, which is slated for export to Vietnam and Thailand. It already has environmental groups greatly concerned.

“We believe that the Luang Prabang dam should not be built. Despite a wealth of scientific information available on the likely impact, dam construction has continued in the face of these dire warnings,” said Pianporn Deetes, Thailand Campaign Coordinator for non-government organisation, International Rivers.

This section of the Mekong is slated to be developed into the new Luang Prabang dam. (Photo: Jack Board)

But crucially for the project’s prospects, it has the support of the Lao government. “Since we are surrounded by emerging markets like, Vietnam, Thailand or China, that means if those countries need the output from this project, of course, we have to develop it,” Dr Daovong said. “People need energy, right?” 

The location is close to the confluence of the Nam Ou River, a major tributary to the Mekong. Here, Chinese developer POWERCHINA is busily assembling seven dams, with the slogan “Construct a Beautiful Tomorrow with Power and Love”. 

POWERCHINA is constructing seven dams on the Nam Ou, projected to generate electricity for export. (Photo: Jack Board)

Through the mist, the incomplete dam’s concrete skeletons loom over the modest waterway, undergoing an accelerated and complete transformation. Many villagers from the impacted areas have already been located to new more modern towns where streets are wide, schools are busy and local residents discuss their new happy lives, while company representatives watch on, within earshot. In other parts of the Nam Ou, relocation and compensation remain in dispute.

The displacement of locals is an inevitable byproduct of earth shifting projects like these.  The future reservoir of Luang Prabang dam means Ban Houy Yor village will be flooded, memory swept aside in the name of progress.

Its people will be given new houses but local opinions are divided about what that means for their futures. “They are drilling here and there. Sometimes they drill so close, the houses are rattling. Yes, we want to move. They tell us to move then we will have to move,” said one elderly resident.

People dislocated from their home villages due to home construction are typically housed in new settlements. (Photo: Jack Board)

“If I move, I don’t know how I will live or make a living. Here, I work in crops. I also keep buffaloes. I don’t want to move but I don’t think I can defy anything,” another resident explained.

Subsistence is life in these humble communities. They thrive and perish with their environment, one which is changing like never before.  

Back at Pak Ou Caves, women from other small riverside villages line the steps to sell miserly colourful bracelets to passing tourists, while nursing their squeamish babies, some crying in the heat. Drought has hit so badly in the past year that they have no other work options and need the extra income to support their families. 

Climate change is biting in Laos and it is one of the reasons the government has admitted it needs to more carefully review its hydropower dependency.

The riverside village of Ban Houy Yor will be flooded and its residents forced to relocate if the Luang Prabang dam project goes ahead. (Photo: Jack Board)


The looming decades suggest climate trauma for the Mekong. And halcyon days on the river may be numbered when forecasts become reality.

It puts the viability of the hydropower industry on the Mekong, likely to be further impacted by the water demands of China, in serious jeopardy. Already Cambodia suffered from severe electricity shortages last year as poor rainfall and lower river levels meant its dams could not operate as planned.

An MRC report shows a predicted mean temperature rise of about 0.8 degrees Celsius by 2030, a number set to rise incrementally throughout the remainder of the century, each increase raising the magnitude and stakes of the impact.

Climate change is expected to bring more drastic changes to life on the Mekong. (Photo: Jack Board)

It also cites a 50 per cent drop in annual Mekong river flow through Laos’ capital city Vientiane over the next 40 years, under a “dried climate scenario”. An average annual cost of the repercussions of floods alone ranges from US$60 to 70 million in the lower basin, according to MRC.

“(Climate change) has caused floods, drought and salinity intrusion. It has also caused temperatures to rise and water flow in the Mekong to fluctuate, as has been seen,” the MRC Secretariat said. “The impacts of climate change will be worsening in the future.”

A 2014 USAID study is more alarming. It calculates that the livelihoods of at least 60 million people in the region would face damages associated with floods, sea level rise and climate-related disease. 

Drought disasters could cost the four MRC-member nations US$615 million annually by 2030, and floods more than five times that. Agriculture and fisheries face tens of billions of dollars of annual stress damage and infrastructure worth at last US$18 billion would be at risk of frequent or permanent inundation.

Sand dredging is adding to the woes of an under strain river system. (Photo: Jack Board)

It is a grim prediction that has the Laos government seeing the need to “think twice” about dam development. “Normally, before climate change, every ten years there is one severe drought year. Now it’s shorter. Some years it is very wet or we have drought and wet together,” Dr Daovong said.

“So it’s very difficult now to operate or focus the output of the hydropower. We have to think more deeply, more broadly and think if we can develop it this way, or another way.”

He cited increased government interest in developing solar energy throughout the country, which due to previous market prices remains unutilised. It would be a welcome development, according to International Rivers, but remains a hollow pledge so far.

“This has not yet been translated into meaningful action, including the suspension and cancellation of hydropower projects,” Pianporn said.

Drought has contributed to food security issues on the Mekong. (Photo: Jack Board)

In the meantime, food security and safety is already a looming issue. Aside from inconsistent fish yields, the chemical-free growing of food along the Mekong is at risk due to degrading soil from a lack of sediment and erosion from wildly fluctuating water flows. 

“Instead of eating organic vegetables, now, we have to eat vegetables that are grown with pesticides and insecticides,” Ormbun Thipsuna, a representative of the Northeast Community Network in 7 Provinces of the Mekong River Basin in Thailand.

‘The burden has been imposed on us, and we don’t have any opportunity to argue or raise our voice against it.  I think the Mekong River right now is so scary. It is so unpredictable. It doesn’t even look like the Mekong anymore,” she said.

The moods and motivations of many locals along the river are ebbing as low as the clear water in front of them. And those working on the Mekong’s health have little hope that salvation of their river is coming.

The sun sets over the Mekong River close to Luang Prabang in northern Laos. (Photo: Jack Board)

“Today, I personally feel more depressed than angry. Ultimately, the four member states in the Lower Mekong Basin do not see Mekong River as a river of the people that needs to be preserved. The language here is to gain benefit,” Montri said.

“There are beautiful words that say the Mekong River belongs to 60 million people, nourishes 60 million people. These are just beautiful prologues, but they are deceptive. The ownership of the Mekong by 60 million people does not exist.”

Additional reporting by Ryn Jirenuwat