But months later, both the review and investigation are ongoing, and work on approximately 50 dams steadily continues.
Dams disrupting the Mekong
Located in the heart of mainland Southeast Asia, Laos is a sliver of a landlocked nation living in the shadows of neighboring tourist hotspots Thailand, Vietnam and Cambodia.
Laos is traversed by the Mekong River, which flows for 2,700 miles from the Himalayan mountains of Tibet through Myanmar, Laos, Thailand, Cambodia and Vietnam, where it empties into the South China Sea.
Of these dams, nine are located in Laos and two are already under construction.
As one of the poorest countries in Asia, Laos hopes to profit from exporting power to neighboring nations.
If all goes to plan, this could mean a total of 429 dams on the Mekong by 2030.
“If many of the dams that are planned are built it will essentially result in a complete transformation of the river system as it’s been known,” said Maureen Harris, Southeast Asia program director at environmental advocacy group International Rivers, which defends the rights of the rivers and the communities that depend on them.
“You’ll see a stretch of the river that has been free flowing and fast flowing completely changed into a series of reservoirs, or lakes with still water, and that will have knock-on effects to the wider ecosystem.”
Those effects include tearing local people from their land, Harris explained, with residents uprooted, resettled and expected to eke out new livelihoods after generations of depending on the river in the process.
Left: A riverside village in the Nam Ou river valley in Phongsaly Province, before dam construction. Right: A resettled village to make way for the Nam Ou cascade hydropower project.
Damming the environment
Life has flourished in and around the Mekong in Laos for millions of years. Each rainy season, the river fills and floods nearby forests and rice paddies before retreating in the dry season to expose fertile soil.
Water buffalo roam its banks and its muddy waters are home to vast amounts of aquatic wildlife, including the endangered Mekong giant catfish and Irrawaddy dolphin.
But environmentalists say the overloading of the river with dams could destroy that ecosystem.
“(These dams) will affect fisheries, fish migrations, livelihoods and economies of communities, like millions of people who depend on natural resources provided by the Mekong basin,” explained Pianporn Deetes, Thailand campaign coordinator for International Rivers.
The study found that dams had disrupted river ecology, caused substantial deforestation, generated loss of biodiversity, released large amounts of greenhouse gases, affected food systems, water quality and agriculture and displaced thousands of people.
“While it might seem attractive to develop hydropower in the country … there needs to be much more of a balance in considering what the tradeoffs and what the losses are,” said Harris.
Who’s fronting the cost?
The Lao government doesn’t have the financial or technical capacity to pursue these projects on its own, so it relies on foreign help.
As such, most hydropower dams in Laos are bankrolled by investors from China, Thailand, Korea, Japan and France, explained Courtney Weatherby, a research analyst with the Southeast Asia program at the Washington-based think tank Stimson Center.
“China is one of the largest (investors): at least 50 projects, and about one third of Laos’ total potential is dependent on Chinese financing, investment and/or construction,” said Weatherby.
In most cases, Laos leases land for the dam to the investor for 25 years or so. After that the dam is handed over to Laos.
Laos sometimes owns a small stake in the projects, or the government might be promised a portion of the electricity to use domestically or sell abroad, explained Weatherby.
While profits from hydropower development across the Lower Mekong Basin could amount to $160 billion by 2040, Laos would obtain just 23% of this share despite the fact that the majority of hydropower projects are planned for the country, according to the council study.
Thailand, on the other hand, could see economic gains of $81 billion, because it is both a major investor and the primary purchaser of Lao electricity exports, according to the study. China, Malaysia and South Korea also stand to profit, researchers said.
However, both Harris and Weatherby cautioned that these figures were probably overvalued.
The key takeaway from the council study, according to Deetes, is that governments should explore other energy options. “Because it is so destructive building these dams,” she said.
But she is not optimistic that Laos will heed the call.
CNN reached out to the Lao government, but it did not respond to requests for comment.
Speaking at the World Economic Forum on ASEAN in September, Prime Minister Thongloun Sisoulith said Laos would continue to study other options for renewable energy, but hydropower development remained a significant source of income.
But the PM added that Laos cannot become a “battery of Asia,” as the country’s capacity to develop electricity is still very limited compared to the demand from neighboring countries.
He confirmed that the government will “continue to take into account” the lessons learned from the July dam collapse.
“In terms of electricity development, we have this commitment to make sure that from now on development of hydropower projects should be based on careful planning and good design,” he said.
But Deetes said most of the decision-making around these projects has been behind closed doors.
They argue that environmental costs are not factored in to the dam approval process and that local communities do not have a chance to participate.
During this process, neighboring countries can assess the benefits and risks of the proposed project and Laos has the opportunity to make adjustments to minimize adverse impacts.
Pressure from international organizations can result in dam developers adopting measures to mitigate environmental impacts, explained Brian Eyler, director of Southeast Asia programs at Stimson Center.
But this is only true for dams on the Mekong, as projects on tributaries are not subject to the same consultation process, he added.
“You can find plenty of dams in Laos that have zero mitigation efforts built into them,” said Eyler. “They’re just off the radar of international attention.”
In Laos, he said, with 55 dams under construction, “it’s almost too much to pay attention to.”
Graphics by CNN’s Gabrielle Smith.