The four-nation Mekong River Commission—Vietnam, Cambodia, Laos, and Thailand—was established with the April 5, 1995 Agreement on Cooperation for Sustainable Development of the Mekong River Basin that established the MRC as a platform for regional cooperation among countries along the region’s major river. As Laos continued to dig itself out from the July 23 failure of a dam in the Xe Pian Xe Namnoy hydropower project in Champassak province, Sidney Khotpanya conducted an interview by e-mail with Mekong River Commission Secretariat (MRCS), asking what caused the catastrophe which has killed more than 30 people and left 117 missing.
RFA: What you think was the cause of the dam break in Laos? Did the dam break incident cause any transboundary impact [downstream]?
MRCS: According to the official information we have received from the Government of Laos, we don’t know yet what caused the dam to fail or break. The incident has not been well captured at this moment, although there has been speculation out there that it was because of this and that.
But officially, no, we don’t have the information yet.
Further analysis based on the information taken from or provided by the site should be taken into account as this will shed some light on the cause. The Lao government has formed a national committee, one of whose tasks is to investigate the cause. The MRCS has offered assistance in this regard, especially in providing technical assistance through human resources to assist the investigation that is due to take place after the rescue and recovery process.
But we wish to bring to your attention the recent Typhoon called ‘Son Tinh’ which, from July 19-22, hit Vietnam and then caused extreme rainfall in Laos on July 22. This in turn created, according to our analysis of water levels on the Mekong mainstream, flooding in both Laos and the downstream countries of Cambodia and Viet Nam.
So, in the case of flooding in Laos and Cambodia, our analysis using the Synthetic Aperture Radar (SAR) satellite imagery shows inundated areas and its situation caused by the collapsed saddle dam and flooded villages downstream as of 25 July 2018.
In terms of water level rise, our monitoring station in Siem Pang district (in Stung Treng province of Cambodia) on the Sekong River, using the observed water level recorded automatically in 15-min interval, showed an increase by approximately more than four meters from 8.39 meters at 3:15 PM on 22 July to 12.47 meters at 2:00 PM on 27 July 2018. The increase happened due to heavy rain and later by large amount of water released from Saddle dam D.
Our initial and preliminary analysis on the extent of the water level rise in Stung Treng due to the dam break indicates an approximately 20-cm incase compared to a normal condition. This is because water flows at Stung Treng are dominated by: The inflows from upstream of the Mekong River from Pakse of Laos; the inflows from the 3S area of Se Kong, Sesan and Srepok Rivers; and the catchment rainfall.
Since the Stung Treng station is dominated by the upstream Mekong inflow, the direct inflow from Paske has a strong connection with its downstream part. If normal condition flow at Stung Treng was based on the actual flows at Pakse, the correlation between Pakse and Stung Treng was developed, and the increased volume during the dam break (critical condition) was calculated based on this correlation.
RFA: Can the MRC do anything to prevent dam breaks from happening in the future? Does the MRC have any rules to protect dam break in the future?
MRCS: There are two situations here for water infrastructure projects on (1) the mainstream of the Mekong River and (2) tributaries of the river.
Under the 1995 Mekong Agreement, any member countries who wish to propose (large) projects on the Mekong mainstream must go through the MRC’s prior consultation process. The prior consultation is part of the MRC’s procedural rules on cooperation on water use of the Mekong mainstream: Procedures for Notification, Prior Consultation and Agreement (PNPCA). Under the Procedures, any infrastructural project using the mainstream water during the dry season within the same basin, as well as during the wet season between two basins, must undergo the prior consultation process. Applicable projects include large-scale irrigation and hydropower development which may cause significant impacts on the environment, water flow and quality of the Mekong mainstream.
In the prior consultation process, with technical and administrative support from the MRC Secretariat, the notified Member Countries will review technical aspects of the project, assess any potential transboundary impact on the environment and livelihoods along the riparian communities, and suggest measures to address those concerns. The Member Countries aim to come to an agreement on how the consulted case should proceed. It is not meant to approve or disapprove the proposed project. This process normally lasts six months, but it could be extended further by the Joint Committee (implementing body of the organization) of the MRC.
However, notified projects on Mekong tributaries, such as the Xe-Nam Noy Hydropower dam, are not required to undergo MRC’s prior consultation process, including assessments. Projects on tributaries follow national laws and regulations.
On top of that, the MRC has put in place a Preliminary Design Guidance for Proposed Mainstream Dam in the Lower Mekong Basin (PDG), which is to provide direction on performance targets, design and operating principles for mitigation measures, as well as compliance monitoring and adaptive management. One of the most important aspects is the dam safety measure that the PDG provides/recommends to developers.
Although the PDG is advisory in nature, the intention is to provide developers of proposed dams on the lower Mekong mainstream with an overview of the issues that the MRC will be considering during the process of prior consultation under the 1995 Mekong Agreement. Responsibility for ensuring compliance with national standards and provisions of the 1995 Mekong Agreement remains with the project developers, though.
With the PDG and PNPCA, developers and owners of dams can design them in a way that corresponds to and complies with dam safety standards. But gaps remain as these are applicable only to the projects on the mainstream, not on the tributaries.