Lower Sesan 2 Hydropower Dam: Brief
Overview
The Lower Sesan 2 (LS2) project is a hydropower dam planned for the lower section of the Sesan River in Stung
Treng Province, Cambodia. The Sesan River is a major tributary of the Mekong River, flowing from Dak Glei in
Vietnam to Stung Treng, where it meets the Mekong River. Together with the Srepok and Sekong Rivers, the Sesan
River forms part of the 3S River Basin, an area abundant in biodiversity and unique ecosystems. The Sesan River is
rich in aquatic life and fish species and the surrounding land and forest is inhabited by rare and endangered
wildlife. Some of Cambodia's oldest indigenous peoples live beside 3S Rivers. Traditional lifestyles are selfsustaining and rely on use of natural resources; from the river and land the local people derive food, livelihoods,
culture and identity.
The LS2 dam is located just below the confluence of the Sesan and Srepok Rivers, and about 25km from the
Mekong mainstream. The project will cost $816 million and publicly available design documents state that it will be
70m high and 8m wide, creating a 33,560 hectare reservoir. Clearing for the dam's reservoir began in April 2013
and in March 2014 construction work commenced on the water diversion channels to prepare for building the
project. The project is expected to be completed by 2018, with capacity of 400 MW and an average output of
1,998 GWh per year.1
Involvement of Chinese companies
The major investors in the LS2 project are Cambodia’s Royal Group, and China's Hydrolancang International Energy
Co. Ltd. These companies are developing the dam through a joint venture, the Hydropower Lower Sesan 2 Co.,
which holds 90% share in the project. EVN International Joint Stock Company, a subsidiary of the Electricity of
Vietnam (EVN) holds the remaining 10% interest in the project. Hydrolancang is a subsidiary of Chinese stateowned energy giant, Huaneng Group. The investment is in the form of Build-Operate-Transfer (BOT) with a
concession period of 45 years, including 5 years of construction and 40 years of operation before ownership of the
dam is transferred to the Royal Government of Cambodia (RGC). 2
Environmental impacts
The LS2 dam will block both the Sesan and the Srepok Rivers, two of the largest rivers in the Mekong River Basin,
and inundate a large area. Due to the project's location, crucial to the fish migration patterns, hydrology and
ecosystems of the 3S Rivers system as well as the Mekong River, the LS2 project is predicted to cause severe
environmental and social impacts. These impacts will be felt most heavily by riverine communities up and
downstream from the project, in Cambodia but also in neighboring countries of Vietnam, Laos and Thailand.
The Sesan and Srepok rivers serve as major breeding grounds for local fish, and the LS2 will permanently prevent
all migratory species of fish in the river (40% of all fish) from reaching these traditional breeding grounds.3 The
dam will have the greatest negative impact on fish of any planned tributary dam,4 reducing fish biomass by 9.3%
across the entire Mekong River Basin, and creating approximately 56 new endangered fish species.5 Further, some
non-migratory fish species will be unable to survive changes to habitat and water quality in the dam’s reservoir.6
1
Mekong Watch, ‘Factsheet on the Lower Sesan 2 Hydropower Project,’ August 5 2013, available at:
<http://www.mekongwatch.org/english/country/cambodia/LS2/index.html>.
2 Law on the Authorization of Payment Warranty of the Royal Government of Cambodia for the Hydro Power Lower Sesan 2 Company, Cambodian National
Assembly, February 2013.
3 Carmichael, Robert. "Work Begins on Controversial Cambodian Dam." Voice of America. 7 May 2013, quoting Eric Baran, World Fish Center. Web. 3 June 2013.
<http://www.voanews.com/content/work-begins-on-controversial-hydropower-dam/1656035.html>.
4 Ziv, Guy; Baran, Guy Eric; Nam, So; Ignacio Rodríguez-Iturbe, Ignacio and Levin, Simon A.; ‘Trading-off fish biodiversity, food security, and hydropower in the Mekong
River Basin’ Proceedings of the National Academy of Sciences of the United States of America, 28 January 2012. According to the study, the aggregate effect of all
proposed tributary dams is a near 20% reduction in fish biomass. After the LS2, the proposed dam with the second largest predicted impact will reduce fish by 2.3%.
5 Ibid.
6 Mekong River Commission. State of the Basin Report 2010. Vientiane: Mekong River Commission, April 2010 at 97.
The LS2 project is also predicted to contribute to a 6-8% reduction in sediment flows on the Mekong, negatively
affecting vital nutrient levels flowing downstream. The impact is much larger than that of other proposed dams.
“Such a large sedimentation loss would reduce the stability of river channels and the Mekong Delta coastline,
increasing erosion and diminishing productivity of the aquatic system and agriculture in the Mekong floodplains
and Tonle Sap lake…”.7
The 3S Rivers account for roughly 17% of the Mekong’s annual discharge. 8 A 2010 ADB report noted that there is
already "a sense that the [region] is approaching some degree of water crisis…” 9 Hydropower projects on the 3S
Rivers will result in significant further alteration of natural water flows in the Mekong and its tributaries, increasing
flows by 63% in the dry season and decreasing flows by 22% in the wet season.10 Such significant flow changes are
"of great concern because [they] could impact habitat downstream by reducing wetland areas in the flood season,
submerging sandbars, changing river morphology, and altering river bank vegetation.” 11
Social, economic and cultural impacts
Scientific studies warn that the environmental impacts from the project will be far more serious and wide-ranging
than those assessed in the project’s environmental impact assessment (EIA). Without further research, it is difficult
to accurately assess the scale of the social impacts resulting from the dam, including the populations to be
affected. However, research estimates that hundreds of thousands of villagers in riverine communities in
Cambodia as well as Vietnam, Laos and Thailand will experience threats to their livelihoods, food security and
traditional practices. The predicted impacts may even exacerbate tensions and jeopardize regional stability.
The reduction in fish biomass of nearly 10% will result in an estimated loss of 200,000 tons of fish catch per year
across the Mekong Basin.12 The total economic value of Mekong fisheries is estimated at US$3.9–7.0 billion per
year.13 In 2008, the total value of Cambodian fishery exports was US$35.8 million. 14 Fishery sales account for nearly
12% of Cambodian GDP,15 and the industry creates over 420,000 primary sector jobs, and over 2 million secondary
sector jobs.16
Fish and other aquatic animals are the primary form of protein in the diet of 75% of rural Cambodians17 and for all
Cambodians, fish constitute 18% of total food consumption.18 In 2012, Cambodians consumed an estimated
625,000 tons of inland fish and other aquatic animals. Long-distance migratory fish (the type most likely to be lost
through dam development) comprised 25% of total fish intake.19 For the average Cambodian, fish and other
aquatic animals contribute 37% of total protein consumed, 28% of total fat intake and 37% of total iron intake.20
7
Ketelson, T, International Center for Environmental Management, cited in Vrieze, P, & Chhorn C, ’The Battle for the 3S Rivers’ The Cambodia Daily, 10 September
2011.
8 TA 6367-REG: Sesan, SrePok and Sekong River Basins Development Study in Cambodia, Lao People's Democratic Republic, and Viet Nam. Asian Development Bank,
August 2011.
9 Sesan, SrePok, and Sekong River Basins Development Study in Kingdom of Cambodia, Lao People's Democratic Republic, and Socialist Republic of Viet Nam. Project
no. 40082. Asian Development Bank, July 2010: 25.
10 Piman, T, Cochrane, T, Arias, M., Green, A., and Dat, N. "Assessment of Flow Changes from Hydropower Development and Operations in Sekong, Sesan and Srepok
Rivers of the Mekong Basin." Journal of Water Resources Planning and Management. 21 May, 2012 at 17.
11 Ibid; at 18.
12Carmichael, Robert. "Work Begins on Controversial Cambodian Dam." Voice of America. 7 May 2013, quoting Eric Baran, World Fish Center. Web. 3 June 2013.
<http://www.voanews.com/content/work-begins-on-controversial-hydropower-dam/1656035.html>.
13 MRC. State of the Basin Report 2010 Summary. Publication. Vientiane: Mekong River Commission, 2010 at 12.
14 FAO. National Fishery Sector Overview: Cambodia. Food and Agriculture Organization of the United Nations, Mar. 2011 at 1.
15 Hortle, K.G. Consumption and the yield of fish and other aquatic animals from the Lower Mekong Basin. MRC Technical Paper No. 16, Vientiane: Mekong River
Commission, 2007 at 12; Fisheries. Mekong River Commission. Web. 5 June 2013. <http://www.mrcmekong.org/topics/fisheries/>.
16 Ibid; at 1.
17 FAO. National Fishery Sector Overview: Cambodia. Food and Agriculture Organization of the United Nations, Mar. 2011 at 8.
18 IFReDI 2012.Food and nutrition security vulnerability to mainstream hydropower dam development in Cambodia. Synthesis report of the FiA/Danida/WWF/Oxfam
project “Food and nutrition security vulnerability to mainstream hydropower dam development in Cambodia”. Inland Fisheries Research and Development Institute,
Fisheries Administration, Phnom Penh, Cambodia, at 4.
19 Ibid; at 5.
20 Ibid; at 5.
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Such a sharp reduction in fish biomass will generate significant food and health security issues,21 and the loss of an
essential food and protein source will result in heightened poverty and malnutrition. These impacts will be felt
sharply in Cambodia, a country where 80% of the rural population already falls under the national poverty line, and
33% of the entire population is already undernourished.22 Only 25% of Cambodians currently have the necessary
levels of energy and only 19% have the required levels of iron.23 A recent study on the impacts of proposed
mainstream dams found that “[a] reduction in the availability of fish and specifically of long-distance migrants,
which is important for the provision of iron, would have a strong detrimental impact on the rural population,
driving iron security even lower and posing a risk to public health.” 24 The study also found that school-aged
children and pregnant women are the most food-insecure and most vulnerable to protein reduction.25
The impacts of the project on sediment and water flows also threaten food security and livelihoods in Cambodia
and neighbouring countries. The LS2 will eradicate 1,290 ha of agricultural land, or one-fourth of wet rice paddy
land in Sesan District, which is of especially good quality.26 Reduced soil fertility and changes to seasonal water
flows across the Mekong River Basin will harm riverbank agriculture, a major source of local livelihoods and
economic security.
For communities forced to relocate as a result of the project, and for many other villagers up and downstream
whose livelihoods are threatened, loss of culture and way of life is a major concern. Directly affected communities
are predominantly indigenous peoples facing the permanent destruction of their spiritual and cultural sites and
traditional lands. These communities fear an irreparable breakdown of community integrity and the
disappearance of traditional practices and knowledge. The resulting losses are incalculable in economic or financial
terms and cannot be compensated through relocation and resettlement plans: they include the disappearance of
unique indigenous cultures, belief systems and traditions and the cultural heritage they represent.
A lack of transparency and accountability
To date, the project developers have provided little or no information to the affected communities about the
impacts of the project or the plans for relocation and compensation and have not afforded local people with an
opportunity to voice concerns and participate in decision-making. The existing EIA report has been critiqued as
inadequate, as it only examined impacts in a limited area around the immediate dam site and failed to consult
properly with affected communities. Further, no information has been provided or consultation conducted with
other communities to be affected downstream in Cambodia and neighboring countries and no study has been
made public regarding the transboundary social and environmental impacts of the project.
Communities in Stung Treng have expressed strong concern about the risks to their livelihoods and survival posed
by the LS2 dam. These communities have already experienced adverse impacts from dams upstream on the upper
stretches of the Sesan River in Vietnam. Villagers assert that upstream dams have caused flooding and changes to
water flow, reduced water quality and decreased fish catch for family consumption. 27 Upstream dams have
damaged the agricultural and fishing livelihoods of local people and led to illness, disease and impoverishment.
Community members have arranged peaceful public demonstrations and other activities to express concerns over
the LS2 dam and frustration at lack of consultation with local people and any proper assessment of impacts on
communities. In December 2013, representatives of communities from the 3S Rivers presented a statement to the
Chinese Ambassador to Cambodia in Phnom Penh urging the Ambassador to visit affected communities and
intervene with the Chinese companies involved in the project.28 They are still awaiting a response.
21Farrell,
Tracy A. "Opinion: Mekong River Dam Threatens Livelihoods and Ecosystems." Cable News Network, 19 Dec. 2012. Web. 4 June 2013.
<http://edition.cnn.com/2012/12/18/opinion/opnion-mekong-river-dam>.
22 MRC. State of the Basin Report 2010 Summary. Publication. Vientiane: Mekong River Commission, 2010, at 43-4
23 IFReDI (2012) at 5.
24 Ibid; at 7.
25 Ibid; at 7.
26 Baird, Ian G., Ph.D. Best Practices in Compensation and Resettlement for Large Dams: The Case of the Planned Lower Sesan 2 Hydropower Project in Northeastern
Cambodia. Publication. Phnom Penh: Rivers Coalition in Cambodia. May 2009, at 34.
27 Community representatives of the 3S Rivers, 'The joint statement of the communities along Sesan, Srepok and Sekong Rivers: Request to Withdraw China’s
Involvement in the Lower Sesan 2 Dam' delivered to Ambassador of the Poeple's Republic of China in Cambodia, 12 December 2013, available at:
<http://www.3spn.org/the-communities-along-the-sesan-srepok-and-sekong-river-submit-their-joint-statement-to-chinese-embassy/>.
28 Ibid.
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Finally, impact assessment studies for the project do not appear to have given due consideration to alternatives
that are more in line with the Cambodian Government’s energy sector development objectives, “to encourage
exploration and environmentally and socially acceptable development of energy resources…” and “to minimize
detrimental environmental effects resulting from energy supply and use…” 29 The Royal Government of Cambodia
has elsewhere emphasized the importance of natural resource protection for sustainable development and
poverty reduction,30 and concern with “improving…food security and nutrition."31 Research indicates that there are
more sustainable and less harmful alternatives for regional power generation through reconfiguration of proposed
dam locations.32 Other studies indicate that recent technological advances make decentralized electricity systems a
viable option for rural Cambodia, including off-grid solar, micro-hydropower, and biomass technologies.33
***
29Cambodia
Energy Sector Strategy. Draft publication. United Nations. Web. 6 June 2013, at 13.
<http://www.un.org/esa/agenda21/natlinfo/countr/cambodia/energy.pdf>.
30National Strategic Development Plan Update 2009-2013: ii. Royal Government of Cambodia.
31 Ibid.
32 Ziv et al (2012): this study found that “75 percent of the tributaries’ total energy could be generated by a [different] combination of dams…” which would reduce
fish biomass by roughly 6 percent instead of 20.”
33 See, e.g., Ryder, Grainne. Powering 21st Century Cambodia with Decentralized Generation: A Primer for Rethinking Cambodia’s Electricity Future. The NGO Forum
on Cambodia and Probe International: October 2009.
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