Credit: MRC

Transboundary impacts of the first two dams on the Lower Mekong to be studied

Mekong experts expect to achieve “practical adaptive management actions” and initial mitigation measures that could help address potential impacts from the dams of Xayaburi and Don Sahong

A pilot program to monitor transboundary environmental impacts from the Xayaburi and Don Sahong dams, the first of its kind, has been announced following the two-day meeting of the Mekong experts and stakeholder representatives held in Nong Khai province last week.  

The developers of the two dams, and technical specialists from Cambodia, Lao PDR, Thailand and Viet Nam, and from the MRC Secretariat, with support from the German based GIZ will work together throughout this monitoring process.

It is aimed at providing advices on measures to address any negative effects from the existing and future Mekong mainstream hydropower projects, said Dr. So Nam, the MRC Secretariat Chief Environmental Management Officer.

The Xayaburi and Don Sahong are the first two dams already built on the mainstream of the lower Mekong River in Lao PDR amid concerns over transboundary impacts which are not yet subject to any serious studies.

During their six-month prior consultation process under the MRC procedures and throughout their construction stage, Cambodia, Thailand and Viet Nam and other concerned stakeholders called for a program to properly and systematically assess impacts from the dams once they are operational.

Dr. So Nam said the Joint Environment Monitoring of Mekong Mainstream Hydropower Projects (JEM) is a response to the call to provide the standard operating procedures for joint environment monitoring of Mekong mainstream hydropower projects.

“The overall objective of the JEM is to systematically collect, generate and share reliable and scientific data and information through a standardized basin wide joint environmental monitoring program on site-specific issues that have cross-national implications,” Dr. Nam said.

“With preliminary findings, we will be able to understand the effectiveness of the dam facilities, including fish passes and sediment flushing gates. From there, we hope to identify some practical adaptive management actions and initial mitigation measures that could eventually help address some of the potential impacts from the two already existing mainstream dams.”

Dr. Nam said the monitoring process will be undertaken from 2020 to 2021. It will allow testing teams to trial and refine proposed monitoring approaches and methodologies that can later be applied at a basin-wide scale and incorporated into the MRC’s core monitoring work.

The pilot program at the Xayaburi and Don Sahong dams will involve monitoring five key disciplines, including hydrology and hydraulics, sediment, water quality, aquatic ecology, and fish and fisheries.

Data collection equipment will be installed in at least three locations in each dam, depending on the discipline. 

At the upper-reach of the dam, there will be a minimum of two monitoring sites that are located at the upstream of the impoundment area and within the impoundment area. At the lower-reach of the dam, there is at least one monitoring site. 

The national teams from each Mekong country will be trained on how to collect the data, using approaches and methodologies.

Once the data are collected, all the teams will work together to analyze and produce “monitoring reports” that will be shared with the public through an MRC’s regional stakeholder forum, website and other communication channels. 

These reports will include initial findings and encountered challenges and shortcomings of the proposed monitoring approaches and methodologies, which will be used to further the JEM program, said Dr. Nam.

Earlier, the group were invited to visit the Xayaburi dam,  and they expressed their opinions in regard to monitoring and data sharing by the dam, saying that the Xayaburi hydropower developer should share information on the dam operation with the lower Mekong countries for better planning and management

While the visitors appreciated the level of openness of the Xayaburi developer, they said the company should continue to work with the MRC Secretariat to regularly share data on dam operation, water flow, sediment transport and fish migration when are available, the MRC quoted the visiting group as saying.

Nhan Quang Nguyen, the representative from a Vietnamese NGO, Centre for Promotion of Integrated Water Resources Management, said observed data and information on sediment and fish migration above and below the dam as well as on energy generation should be shared.

“Transparent and timely sharing of this information could help the people and relevant authorities make better planning”, he said.

Mr. Chea Narin from the Cambodia’s Ministry of Mines and Energy echoed the suggestion, saying Cambodia would like to see the Xayaburi dam developer and owner continue addressing the past concerns and sharing more information with the MRC Secretariat, referring to data sharing from the dam that helps to address changes in water flow, eco-system, sediment transport and livelihood of the lower countries and people.

“The dam operation rules should also be shared with the MRC Secretariat and the other MRC member countries so that coordinated operations of the dams on the mainstream of the Mekong could be established,” he said.

A researcher from Thailand’s Kasetsart University Patchara Jaturakomol said that the absence of water flow data sharing from the Xayaburi dam with the public and lower countries made her think that the Xayaburi was storing water.

“It’s hard not to think that the dam isn’t storing the water when you saw the water levels on the upstream and downstream of the dams are different,” she said, adding she would like the developer to share this data officially with the public to allow the “data speaks for itself”.

Pianporn Deetes, Thailand campaign coordinator at the International Rivers, has made some remarks on the planned study.

She said the JEM project has far lagged behind the real impacts which have been occurring along the Thai-Lao border following the dam operation, and these are intensifying.

She has questioned whether or not the study could be taken as a timely and justified process to help guide a decision-making and mitigation measures. The two dams, she said, had no transboundary impact assessements accompanied in the first place, therefore any mitigation measures that follow become questionable.

“The fact is the budget set to support the study is the public money while the dam developers are not yet responsible for anything still?,” said Pianporn.