On behalf of Rivers Coalition in Cambodia (RCC), an alliance of civil society organisations working to protect and restore river ecosystems and river-based livelihoods in Cambodia, we have called upon the Thai and Lao governments this week to immediately halt all construction work on the proposed Xayaburi hydropower project in Northern Lao PDR.

We believe the governments must wait for the results of the agreed upon Mekong River Commission (MRC) study on the trans-boundary impacts of the Mekong mainstream dams, a study that was agreed upon by both the governments of Thailand and Laos.

In April 2011, our government, along with Thailand and Vietnam called for a study of the Xayaburi Dam’s transboundary impacts and for further consultation meetings among the riparian countries, especially with proposed dam affected communities along the Mekong River from Lao to Vietnam’s Mekong Delta, neither of which has yet to occur.

We, the representatives of civil society organisations and riparian communities in Cambodia, are very concerned about the current construction activities occurring at the site of the Xayaburi Dam, the first dam in a cascade of 11 planned projects. The Mekong River Basin is home to 65 million people, most of whom are poor and receive between 40 per cent to 80 per cent of their protein from inland fisheries.

Numerous studies, including the Strategic Environmental Assessment (SEA) report commissioned by the MRC in 2010, have shown that the proposed 11 hydropower dams on the Mekong River mainstream, including the Xayaburi Dam, will block fish migrations and cause severe damage to the river’s ecosystem and biodiversity.

The dams will also block sediment flows and inundate agricultural lands along the Mekong River. As a result, the livelihoods of millions of Cambodian people, as well as Thai and Vietnamese people, who rely on the river and its tributaries, will be badly affected.

Thailand’s Ch Karnchang Public Company Limited is the main developer of the Xayaburi Dam. In October 2011, the Electricity Generating Authority of Thailand (EGAT) signed a Power Purchase Agreement (PPA) with the Xayaburi Power Co Ltd to import about 95 per cent of the electricity generated by the Xayaburi Dam.

Moreover Pöyry, a consultancy commissioned by the government of Laos to conduct a compliance review of the project, is a World Bank blacklisted company and yet now is the project’s lead independent engineer. Furthermore, Compagnie Nationale du Rhône (CNR), a French company that the Lao government hired in late 2011 to provide further analysis of the Pöyry report, did not address the dam’s impacts on fisheries and offered unproven mitigation advise on sedimentation flow despite the fact that proper baseline studies have yet to be carried out.

A transboundary environmental impact assessment has also never been carried out for the project, thereby making it impossible for the companies to know the full severity of the dam’s projected impacts on Cambodia and other Mekong countries.

Despite the fact that project construction is now underway, the four Lower Mekong countries have not yet agreed to construct the Xayaburi Dam. According to the 1995 Mekong Agreement, the four countries must reach a joint decision under the Procedures for Notification, Prior Consultation and Agreement (PNPCA) before the project is implemented.

The Cambodian and Vietnamese governments are strongly concerned about the impacts of the project and have called upon the Lao government to halt construction and wait for the results of the joint study.

With the irreversible negative impacts of the Xayaburi Dam, we urge Prime Minster Yingluck to take responsible action by decisively cancelling the Power Purchase Agreement (PPA) and ordering Ch Karnchang to stop all construction activities until further studies are conducted.

We also urge Yingluck to order Ch Karnchang to carry out a transboundary impact assessment for the project, which is an international best practice for a project of this nature on a shared river. Ch Karnchang should also ensure that consultations take place with the public, particularly with people whose livelihoods are dependent on the Mekong River and the Tonle Sap Lake.

Lastly, if Ch Karnchang refuses to do this, we urge the Thai government to block the loans of the four major Thai banks (Bangkok Bank, Kasikorn Bank, Krung Thai Bank and Siam Commercial Bank) financing this project.

As a shared river, we hope that Prime Minister Yingluck will uphold Thailand’s responsibility to protect the Mekong River, as our common future depends upon the rich ecosystem services the river provides many of us on a daily basis.

Chhith Sam Ath is the Executive Director of the NGO Forum on Cambodia and Chea Phallika is Project Coordinator of the NGO Forum’s Hydropower and Community Rights Project and the Coordinator of Rivers Coalition in Cambodia (RCC). These views are those of all members of the RCC.