This article originally appeared in The Ecologist.
The construction of the Don Sahong Dam in Laos PDR must be halted until full information on the project’s impacts – in particular the fate of millions of fish that migrate each year through the Hou Sahong channel now being dammed – has been published, writes the Save the Mekong Coalition in this open letter sent today to the project developers.
The food security of thousands of people in the Mekong Basin is dependent on many of the migratory fish species which have traditionally passed through the Hou Sahong channel, which the dam threatens to block.
Dear Messrs. Goh and Thiravong,
We are a coalition of concerned non-governmental organizations and civil society groups from the Mekong and beyond with interest in protecting the resources of the Mekong River and the rights of Mekong communities.
The Save the Mekong Coalition has expressed concerns over the development of the Don Sahong Dam in Champassak Province, Lao P.D.R, for many years. We have addressed numerous letters and statements to the Mekong River Commission (MRC) and to member governments, and closely monitored the project’s Prior Consultation process.
Members of our coalition have also sent letters to communicate concerns over the project and request a meeting with Mega First Corporation Berhad (MFCB) and the project developers. These requests did not receive a response. 
We write to reiterate our serious and ongoing concern over the construction of the Don Sahong Dam. For a project with a relatively low generating capacity, due to its location in an area critical to Mekong fish migration, the potential impacts of the project on regional fisheries are severe.
This dam could undermine the food security of thousands
The food security of thousands of people in the Mekong Basin is dependent on many of the migratory fish species which have traditionally passed through the Hou Sahong channel. Inadequate information has been made available to date regarding the scale and scope of the project’s impacts, the ongoing studies and monitoring efforts that are informing the project’s ‘adaptive and flexible approach’ to mitigation, and confirmation of the implementation and efficacy of the project’s mitigation measures.
We restate the concerns raised by Mekong governments in their formal reply forms during the Prior Consultation process for the Don Sahong Dam under the 1995 Mekong Agreement.  These include requests for a delay to the project to undertake further studies, provision of baseline information, a transboundary environmental assessment, and studies evidencing the efficacy of proposed mitigation measures.
It remains unclear whether and how the issues raised by neighbouring governments have been addressed, and yet construction of the Don Sahong Dam has proceeded without transparent information or closure on these questions.
In addition to these outstanding issues, we are very concerned that not all mitigation measures outlined in the project’s 2013 Environmental Impact Assessment (EIA), will be effectively implemented by the project developers.
The EIA states that the Don Sahong Hydropower Project’s (DSHPP) strategy for mitigating direct fisheries migration impacts will be guided by the MRC requirement to provide “safe passage for 95% of the target species under all flow conditions”. 
The strategy includes an express commitment by DSHPP “to implement a fish exclusion screen and bypass system in the upstream section of the Hou Sahong channel to reduce the number of fish passing through the turbines.”  This commitment is also reflected in the developers’ comments in response to the MRC’s review of the project. 
According to the EIA, the measures for a fish screen diversion and bypass structure are to be based on ongoing monitoring and “an adaptive and flexible approach” that “ensures a commitment for implementing additional structural mitigation measures if and when they are needed.”  While the developers have conducted a preliminary trial on an acoustic fish deterrence system, the study provides little reassurance as to whether specific measures will be adopted and what form they will take. 
Although the developers have stated that extensive fish monitoring will be undertaken, limited information has been made available regarding baseline data and the ongoing monitoring of fish species and their migration patterns. Recent studies on the company website do not include reports detailing monitoring data and analysis since project construction commenced in January.
Halt construction until concerns have been addressed!
People potentially affected by the project currently have little means to seek accountability. This includes transparency over the project’s impacts and guarantees that the full range of measures available will be implemented to mitigate adverse impacts on fish migration and the threats to local communities and regional food security.
We therefore call on the project developers to:
- Confirm that all necessary measures, including screen and bypass systems to divert fish from entering the Hou Sahong channel and turbines, are being implemented to ensure mitigation of the project impacts is as effective as possible;
- Release details of the fish screen and bypass system design and information as to how the measures will be developed to cater for fish species in the area;
- Release the results of ongoing fisheries monitoring studies that show how fish migration behaviour is adapting to project construction;
- Halt construction of the project until comprehensive information regarding the project’s environmental and social impacts and addressing the concerns raised by Mekong governments has been made publicly available.
Save the Mekong Coalition, 17th November 2016.
Mr. Goh Nan Kioh, Chairman, Mega First Corporation Berhad, A-12-01, Level 12, Block A, PJ8, 23 Jalan Barat, Seksyen 8, 46050 Petaling Jaya, Selangor Darul Ehsan, Malaysia.
Mr Sisavath Thiravong, Chairman of the Board, Chief Executive Officer and Managing Director Electricite Du Laos (EDL) Lao-Thai Friendship Road, B. Thongkang, Sisattanak District P.O Box 309, Vientiane, Laos P.D.R.
Both Ends (The Netherlands)
Community Resource Centre Foundation (Thailand)
EarthRights International (United States and Southeast Asia)
Fisheries Action Coalition Team (Cambodia)
Focus on the Global South (Thailand and Southeast Asia)
International Rivers (United States and Southeast Asia)
Law and Policy of Sustainable Development Center (Vietnam)
Living River Siam Association (Thailand)
Mangrove Action Project (Asia Office – Thailand)
Mekong Community Institute Association (Thailand)
Mekong Watch (Japan and Southeast Asia)
Ms. Ame Trandem (The Netherlands)
Oxfam (Mekong Region)
The Corner House (United Kingdom)
Tonle Sap Waterkeepers Alliance (Cambodia)
Vietnam Rivers Network (Vietnam) WARECOD (Vietnam).
1. Letters to Mega First Corporation Berhad were sent on 19 November 2013 and 29 September 2014.
2. Mekong River Commission, ‘Reply Forms to Prior Consultation: Don Sahong Hydropower Project’.
3. Mekong River Commission, ‘Preliminary Design Guidance for Proposed Lower Mekong Basin Hydropower Schemes’. 31st August 2009, at 12.
4. Environmental Impact Assessment (EIA), Don Sahong Hydropower Project (2013), Section 5, 18-19.
5. EIA Report (2013), Annex A: Response to Mekong River Commission Comments Received on the Don Sahong Hydropower Project 2007 EIA Documents, at A-5.
6. EIA Report (2013), Section 5, 21.
7. Don Sahong Power Company, ‘Acoustic Fish Deterrence System Preliminary Trial’, July 2016.