Backwater modelling for Pak Beng dam demanded following growing concerns over recent flooding in Thai-Lao border communities

The potential backwater from the dam could cause lasting adverse impacts on the Mekong ecosystems, people’s livelihoods, as well as the borderline between Thailand and Laos, according to the communities and concerned parties examining the issue including Parliament’s environmental standing committee

The Lower House’s Land, Natural Resources, and Environment Standing Committee last week invited concerned agencies and representatives of the dam developers to give information to it to clarify unsettled issues including backwater effects from the Pak Beng dam project planned on the Lower Mekong in Laos’ territory but could possibly send impacts to Thailand’s territory in the North.

Representatives from both companies of Gulf Energy Development, a co-developer of the dam project, and Team Group, hired to conduct the latest transboundary impact assessment for the project, were absent, declining the committee’s invitation to attend the meeting.

The meeting was held following the committee’s recent trip to the communities along the Thai-Lao border, which could be affected by the dam, to update the situation and listen to representatives of the communities and local governments and organisations to gauge views about the project.

They were informed about several flaws concerning the development of the project, from the lack of thorough public consultation to the possible impacts of the dam project, especially its backwater effects.

So, modelling of the backwater in the areas, from Wiang Kaen to Chaing Khong and Chaing Saen districts, was highly required to help settle concerns among the communities. It has been absent although the EIA was conducted by the dam developers whereas its transboundary impact assessment focused only on river flows downstream.

As noted by Montree Chanthawong of the non-profit Mekong Butterfly, who presented concerns and observations on behalf of the communities, the dam developers’ studies mainly focused on hydrological changes in the mainstream river, not its tributaries and adjacent areas.

At the committee’s meeting, a representative of the Office of National Water Resources (ONWR), acting on behalf of the Thai National Mekong Committee (TNMC) to follow up on the dam development, confirmed the committee the absence of the modelling. The representative said the consultant team is conducting a new transboundary impact study and running modelling to see possible impacts in various dimensions including hydrological changes and cumulative effects. The new study is expected to be completed by the end of this year, the ONWR representative said.

So far, the dam developers are reviewing and revising the dam designs following concerns over fish migration as well as sedimentation. They have not yet started the construction of the dam yet, except for building a bridge and some access roads to the construction site, the ONWR representative said.

The absence of backwater modelling for the Thai communities was also confirmed by a representative of the Water Resources Department at the meeting. In 2019, the department installed some water monitoring stations to measure the water levels there and mapped areas at risk. They learned about possible backwater effects if the dam was operational. At 340 metres above sea level, as described in the dam’s design, the water monitoring stations could also be flooded, apart from the current impacts caused by China’s dams upstream.

“The situation would be further complicated, “ said the representative of the department.

I A video clip presenting a graphic of the Pak Beng dam project. Credit: MRC

Pak Beng dam

The Pak Beng dam project is the first in the cascade of 11 hydropower projects on the lower section of the Mekong River, and the third proposed to the Mekong River Commission (MRC) for the 6-month prior consultation process, after the Xayaburi and Don Sahong dams.

According to the project documents submitted to the MRC by Lao PDR in late 2016, the dam site is located in Pak Beng District, Oudomxai Province. It’s about 530 km downstream from the Jinghong Dam on the Upper Mekong River in China, 180 km from Chiang Saen District in Thailand, and around 100 km from the Thai-Lao border in Wiang Kaen district. It’s around 174 km upstream of Luang Prabang and 258 km from the Xayaburi dam, respectively.

The project was first developed by Datang (Lao) Pak Beng Hydropower Co., Ltd. with an investment worth around US $2,372 million to build a 912-MW run-of-river dam with a total storage capacity of 559 million cubic metres at a normal water level of 340 metres. It is meant to supply up to 10% of the power produced by the project to Électricité du Laos (EDL), and the surplus power will be supplied to Thailand, according to the documents.

The project officially entered the prior consultation process in late December 2016, which was then completed in June 2017. Technical reviews among technical experts were held alongside national and regional consultations. The Water Resources Department, an organiser of the activities, was reported to hold four national meetings, but none were organised in Chiang Khong and Wiang Kaen districts, which are potentially affected by the dam the most. The fourth, which was held in Chiang Saen district, was merely a conclusion session of the first three consultations, according to the Supreme Administrative Court’s ruling document.

The potential dam impacts at that time including the backwater effects had been left unaddressed to the residents concerned before they realised that it progressed with the power purchase agreement endorsed in mid-2022.

At the meeting of the National Energy Policy Council (NEPC) chaired by PM Gen Prayut Chan-o-cha on May 6, it resolved at once to assign the Electricity Generating Authority of Thailand (Egat) to proceed with power purchase agreements with the developers of three Mekong dams; Luang Prabang, Pak Lay, and Pak Beng.

It was updated about the developer of the Pak Beng project, which is Pak Beng Power Co., Ltd. (PBPC), a joint venture registered in Lao PDR, with China Datang Overseas Investment Co., Ltd. holding 51% of the shares, and a Thai company, Gulf Energy Development Public Co., Ltd. holding 49% of the shares. The contract will last 29 years.

Egat’s representatives told the meeting held in the areas late last year by the National Human Rights Commission (NHRC) that it had signed a contract with the dam developer already, leaving the residents there stunned once again. The commencement date was set for January 1, 2033. (Read: Power purchase agreement for Pak Beng dam signed: EGAT)

At the committee’s meeting, Egat’s representatives said the agency could not disclose the conditions set under the contract. The representatives just briefly said Egat had imposed conditions for the dam developer to follow while signing the power purchase agreement, demanding it to conduct a new transboundary environmental impact assessment study and submit it on the day the company will enter its loan agreement, which is expected to be by the end of this year.

The study must follow laws and regulations available and Egat will have 60 days to review the study results and ask for views from the experts concerned, including those from the ONWR, Egat’s representatives said. The dam developer is also required to submit a review report every year. However, Egat could not disclose details of the study and it needs to ask for permission from the dam developer if the committee wants to get more information regarding the ongoing study or the contract.

Asked by the committee’s chair, Dr. Poonsak Chanchampee, if the dam is needed, Egat’s representatives replied; “The project is under a cooperative framework on power development between Thailand and its neighbours and addressed in the new Power Development Plan. As Egat has entered an agreement with the dam developer, it’s necessary to proceed with the project.”

Meanwhile, representatives from the Treaties and Legal Affairs Department and the Navy shared similar concerns about the backwater effects on Thailand’s boundary in the Mekong River in the areas, agreeing that the backwater could affect the current thalweg in the river the two countries adhere to as their river boundary following the Siam-French boundary treaty of 1926.

Thai officials would do every way to protect the country’s rights, they said.

The concerns

In communities like Muang Yai and Huai Luek in Wiang Kaen district bordering Thailand and Laos, the residents have considered that their concerns about the backwater effects from Pak Beng are valid, considering similar water levels brought by recent flooding in this rainy season.

As noted by the residents, rainfall this season was excessive, bringing excess water to flood the districts from Chiang Saen, to nearby Chiang Khong, and Wiang Kaen downstream since early August. The water also came from the Mekong River, of which its increased levels were exacerbated by run-offs upstream, prompting the residents to suspect that China’s dams could have a role in releasing excess water downstream, the speculation that was later denied by Chinese representatives. On some days, the water levels were recorded beyond 350 metres above sea level, according to Rak Chaing Khong Group, which has been monitoring changes in the river.

By mid-September, a number of residents in the areas saw floodwaters from the Mekong River run into its tributaries and flood their rice fields, corn fields, and pomelo orchards, causing them to lose extensive income. For instance, in Yai Nuea village alone, the villagers can make income from their pomelos worth over 100 million baht a year as they are exported fruits, according to Phathai Namchai, the village head.

A former village head of Huai Luek village, Thongsuk Inthawong, urged the committee when it visited his residents late last month to come up with policy recommendations to policymakers to reconsider the Pak Beng dam project as it’s not worth building, considering the lasting impacts it would cause on people’s livelihoods here as well as the Mekong ecosystems.

“You want to produce electricity, but what about us? how can we live from then?” he asked, stressing that the dam project must be scrapped immediately.

l The flooding around the Pak Ngao river mouth in late August before it dried in late September. Credit (1st photo): Piyanan Jitjang/ Rak Chiang Khong Group

Pianporn Deetes, Thailand and Myanmar Campaigns Director of the US-based International Rivers, who questioned the river governance of the dam project, said concerned parties still have time to reconsider the project and put it on hold as the new study has not yet been completed and the loan agreement is not signed. 

“It’s quite clear from the flood incidents that the areas will potentially be flooded if the dam is built. How can we make up for the loss of the people if their properties are flooded like this,” said Ms. Pianporn, while urging the committee to consider proposing the review and scrapping of the project to the government.

Dr. Poonsak noted his observations during the visit that the backwater effects of the dam were critical and needed to be addressed clearly as it could affect the country’s boundary. That’s part of the reason why the modelling was necessary.

The lack of information was a critical issue about this project, which reflected its transparency and accountability. Its procedures became challenging both at the national and regional levels as there were no effective mechanisms to deal with such a transboundary development project, he pointed out.

Dr Poonsak noted after the committee’s meeting that there were still issues that were left unaddressed, the backwater included, and the committee will request more information from concerned agencies to accompany its consideration and recommendation to the government.