During a state visit by Myanmar’s disputed president Min Aung Hliang to the Lao PDR on July 4, representatives from the governments of Laos and Myanmar signed a joint agreement announcing their interest in the construction of a new dam along the Myanmar-Lao border on the Mekong mainstream. 

The announcement, which has caught the Mekong watching community completely by surprise, comes as part of Min Aung Hliang’s charm offensive to shore up bilateral ties around Myanmar’s bordering countries amidst widespread condemnation of his pathway to power. For decades, mainstream Mekong dam plans have been published and circulated by the Mekong River Commission (MRC) member countries of Cambodia, Laos, Thailand, and Vietnam. Even China, which shares zero information about its Mekong dam operations, has long mapped out the locations of its 19 Mekong mainstream dams — 12 of which are now fully operational. 

A Mega-Dam of Unspecified Design

The joint agreement includes a 34-month feasibility study on the unnamed dam, so for now, this project is an idea without a blueprint. The dam would straddle Myanmar and Lao PDR territory somewhere above the Golden Triangle along the once-restive and secluded 180km Myanmar-Lao border portion of the mainstream. Engineers likely used elevation maps and hydrological data to estimate the dam’s potential power generation capacity of 2,790MW. No other dam on the Mekong mainstream in Laos is projected to  have the massive power generation capacity of this new mega-dam. The proposed Sambor Dam on Cambodia’s portion of the mainstream would be similar in power generation capacity with a projected 2,600 MW. However, the Cambodian government has put a moratorium on this dam and another along its mainstream due to concerns about downstream impacts to the Tonle Sap Lake — the world’s largest inland fishery and food security guarantor for Cambodia’s population.

While Myanmar only sits as an observer country to the MRC, Laos is a member and a signatory of the 1995 Mekong Agreement, an international agreement that limits the size and design of dams on the mainstream by ensuring that dams built within member country territory adhere to specific rules for maintaining minimum and maximum flows. These rules make it unlikely for the dam to be designed as a large seasonal storage dam like China’s Xiaowan Dam (4,800 MW) or Nuozhadu (5,850 MW) farther upstream. In order to comply with the Mekong Agreement rules, this new dam will likely be a run-of-river scheme with no seasonal storage like the Xayaburi Dam (1,285) or the eight other dams built, under construction, or planned on the mainstream in Laos. Still, generating 2,790 MW of electricity from a run-of-river scheme will likely be a difficult technical undertaking.

Stimson’s Mekong Infrastructure Tracker shows that no construction companies in Myanmar and Laos have ever built a dam of this scale on the Mekong. Large dams in Myanmar and Laos are typically financed by a foreign investor and built by a foreign contractor who will own and operate the dam for a few decades before handing off ownership to a joint government entity. Most likely,  a Chinese construction company will eventually sign up to build the dam. Chinese companies have built most of the dams within a wide radius of this proposed dam. Further, China’s Jinghong Dam (1,750 MW) will be located upstream of the new dam, and the majority-Chinese-owned Pak Beng Dam in Laos (912 MW) is located farther downstream. A Chinese operator will likely seek to coordinate flows for maximum power generation or disaster risk management between the three dams. Min Aung Hliang is also resuming talks with Chinese firms to build the controversial Myitsone Dam (6,000 MW) on the Irrawaddy upstream in Kachin State, Myanmar. So, the new dam could be part of a renewed push by China to build more dams in mainland Southeast Asia. 

Impacts and Benefits

Considering impacts, this area of the Mekong is not densely populated, but communities living along the mainstream and tributaries that will be inundated when the dam’s reservoir fills will be forced to relocate. If the dam is operated as a run-of-river scheme, it will likely not deliver severe impacts to the Mekong’s natural flow regime (as China’s large seasonal storage dams are proven to do). It is even possible that the new dam, if built, could mitigate sudden releases of water from China’s Jinghong dam that send damaging waves more than to 300km downstream. Those waves have been documented to flood riverside farms and communities, whisking boats and farming assets into the river. However, this should not be a justification for the dam to move ahead. The dam’s largest impacts will be the trapping of sediment and the blocking of fish migration through this section of the mainstream. Fisheries in this part of the Mekong have all but collapsed, and this new dam will only exacerbate the problem.

Most benefits from the dam will go to the construction companies that build the dam, and electricity consumers who live far away in urbanizing areas of mainland Southeast Asia. Additionally, Chinese cargo boat captains who navigate the river between China and the Golden Triangle for trade purposes will benefit from the calm waters of the long reservoir created by the dam. Depending on where the dam is placed, they will no longer have to navigate the long and treacherous canyons of the Mekong that form the Lao-Myanmar border.

However, MRC studies demonstrate that the impacts and risks of mainstream dams far outweigh the benefits, particularly to communities who live along the river’s course. 2,790 MW of power generation can be derived from a portfolio of less damaging renewable energy projects. 

Role of MRC and Mekong Watchers?

Since this dam will partially sit within Lao sovereign territory, eventually the Lao PDR government will need to officially notify the MRC Secretariat of its intent to build this dam as required by the 1995 Mekong Agreement. Because of its position on the mainstream, the dam is also required by the Mekong Agreement to go through the transparent PNPCA (Prior Notification, Prior Consultation, and Agreement) process carried out by the MRC Secretariat, including a technical review of the dam’s design and mitigation plans and a series of public consultations held in every MRC member country. As the feasibility study is only now just kicking off, these MRC processes likely won’t commence for three to four years.

If the Lao PDR government chooses not to notify the MRCS of this mainstream Mekong dam that clearly falls within a portion of its territory or chooses not to pursue the PNPCA consultative process due to a kind of loophole logic related to a portion of the dam falling within a non-MRC member country, then this would mark a further erosion of the 1995 Mekong Agreement. Similarly, designing a large storage dam that is operated outside the flow rules stated within the 1995 Mekong Agreement would also erode the long-practiced norms and standards established by the four member countries. The sanctity of the 1995 Mekong Agreement is often tested: Lao PDR waited for 18 months to notify the MRCS about the construction of the Sekong A Dam in 2021, and in its notification to the MRCS, Cambodia mislabeled the Funan Techo Canal as a tributary project when it clearly is a mainstream project, thereby skirting the PNPCA process.  Mekong watchers should press the Lao and Myanmar government for more information on this new and controversial project and raise awareness around potential violations of the 1995 Mekong Agreement. Local civil society organizations throughout the Mekong should raise their concerns about potential impacts to their communities and livelihoods. Importantly, not all planned mainstream Mekong projects proceed with construction, as evidenced by Cambodia’s 2020 moratorium on mainstream dams and stalled processes looming around other proposed Mekong mainstream dams in Laos. There is plenty of time to push for meaningful change around this new dam, which, eventually, given its size and location, could turn into the Mekong’s most controversial mainstream project.