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Mekong Watch Fact SheetThe Don Sahong Dam (on the Mekong Mainstream)(Revised January 2016.)■Location
Khong District, Champasak Province, southern Laos. Construction is planned for the Hoo Sahong
Channel that flows through a broad expanse of wetlands (Siphandon) created by the Mekong river,where it splits into several streams.
■Project Proponents
・Don Sahong Power Company: Ground Roses Ltd. holds a 79％ share; Silver Acreage Ltd, 1％; andElectricite Du Laos (EDL), 20%.
・The dam will be operated partly by the Mega First Corporation Berhad (MFCB), but MFCB will
entrust the technology, procurement and construction to Sinohydro International Corporation ofChina on a contract period of 50 months for U.S.$320 million.
■Project Funding and Sources
The cost of the project was announced as $300 million, but in November 2013, Lao government
officials said it had risen to $723.1 million. The funding sources have not been determined yet.

Hoo Sahong Channel, planned construction site (dry season)

Hoo Sahong location (source: EIA of DSHD)■Project Outline
The Don Sahong Dam will be a 260 MW hydroelectric dam built on a channel of the Mekong
mainstream called Hoo Sahong, located in Laos less than two kilometers upstream from theCambodian border. The company in charge, Don Sahong Power Company, is 79% funded by
Ground Roses Ltd., 20% by Silver Acreage Ltd. and 1% by EDL. According to newspaper sources inlate 2015, the dam is expected to generate about 2,000 gigawatt-hours annually, commencing
commercial operation in 2019 or 2020. The electricity will be sold to EDL to supply demand insouthern Laos.

■Conditions
The Malaysia-based MFCB conducted a survey in March 2006 in connection with an agreementwith the Lao government for an 18-month feasibility study on the Don Sahong Dam. The Laogovernment employed the consulting firms AECOM of Australia and New Zealand and SMEC ofNew Zealand to oversee development. Later, the Lao government received an environmental
impact assessment from the Australian Power and Water Corporation (APW). The results of thesesurveys of the dam were withheld from the public for a long time, but in October 2013, the Laogovernment notified the Mekong River Commission (MRC), of which it is a member country, that
construction would start, and released the environmental impact assessment. In addition, the Laogovernment declared that the dam construction site was on just one of 17 channels of the MekongRiver, accounting for a mere 5% of the total volume of the river’s flow, so it would not be recognized
as a mainstream dam and there would be no need to discuss it with neighboring countries. To thecontrary, however, in the strategic environmental assessments of mainstream dams entrusted tothe MRC, the Don Sahong had always been treated as a mainstream dam. The Don Sahong Power
Company was established in March 2015 to spearhead the project, and the following October,
MFCB entrusted the China-based Sinohydro International Corporation with engineering,procurement and construction for the dam under a U.S.$320 million contract period of 50 months.
MRC member countries downstream from the dam, Vietnam and Cambodia, have repeatedly
expressed criticism of this dam’s construction, but the Lao government has made no move toreview its plans.
■Negative impacts of the dam
Construction of the Don Sahong Dam will have the following irreparably negative impacts on thespecial natural environment of the Mekong River, the rare plants and animals that depend on it,and the livelihoods of the people supported by the Mekong Basin’s fish species, more than 80% of
which are thought to be migratory.
Effects on Fisheries
A report issued by the World Fish Center in July 2007 (see Reference 4) pointed out that the fish
catches of the Mekong River were significant not only to livelihoods and food security in the region,
but the fisheries of the Mekong Basin countries have economic significance estimated at about $2
billion a year. The fish catch from the Mekong Basin fisheries is estimated to have an economic
value of $2.1 to 3.8 billion a year, and a retail value of $4.2 to 7.6 billion (see Reference 4). Inaddition, the group of cascades known as the Khone Falls constitute the only major waterfall in
the lower Mekong Basin, and are an important fishing site on the Mekong in this area. An
evaluation of the impacts of Mekong mainstream dams on fisheries published by the Interim
Mekong Committee Secretariat in 1994 noted that the Khone Falls constituted “an ecologicallyunique area” that is essentially a microcosm of the entire lower Mekong River,” and that “such asite is so rare in nature that every effort should be made to preserve all of Khone Falls from anydevelopment” (see Reference 3).
Special Features of Hoo Sahong
Hoo Sahong is the only channel in the Siphandon region with a gentle enough gradient that fish
can pass through it year-round. The Don Sahong Dam would block this important migratory route,threatening the livelihoods of people who depend on fisheries in four countries, Thailand, Laos,
Cambodia and Vietnam. In their 1996 newsletter, the Mekong River Commission noted that “theblocking of Hoo Sahong could devastate much of the most important Mekong River fisheries inLaos” (see Reference 1).
Effects on Rare Species and Tourism
The dam is to be located just upstream of where Mekong Irrawaddy dolphins are found. Only
about 80 of the dolphins remain in the Mekong River, mostly in Cambodia, but five survive in Laos.
It is feared that dam construction could cause vibrations and reductions in fish numbers,
threatening the existence of the dolphins, which feed on the fish. The dolphins, together with theKhone Falls cascade group, are an important tourist resource in this area (see Reference 5).

Doubtful Effectiveness of Mitigation Measures
Drawing upon research to date on disruption of fish migrations, a World Fish Center reportstressed that “despite various attempts, there are so far no examples of effective measures in theregion to mitigate the effect of dams on fisheries” (see Reference 4). The construction of “run ofriver” dams in the Mekong Basin has had devastating environmental and social impacts, as wasclearly seen in the case of Thailand’s Pak Mun Dam.
【References】
1) Baird,I.G.. 1996. Khone Falls fishers, Catch and Culture (MRC newsletter). Vol.2 No.2 November 1996.
2) International Center for Environmental Management (ICEM). 2010. Mekong River Commission (MRC)

Strategic Environmental Assessment (SEA) for Hydropower on the Mekong Mainstream: Fisheries Baseline
Assessment Working Paper. Vientiane, Lao PDR: MRC.

3) Mark.T Hill and Susan A.Hill. 1994. Fisheries Ecology and Hydropower in the Mekong River: An Evaluation of
Run-of-the-River Projects. Mekong Secretariat, Bangkok, p.90.
4) World Fish Center. 2007. The Don Sahong Dam and Mekong Fisheries, A science brief.
5) World Wild Fund. 2007. The Don Sahong Dam and the Irrawaddy Dolphins, WWF Science Brief.