Lower Sesan 2 under construction(Photo taken on 27th July 2015)

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E-mail: info@mekongwatch.org
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12th November 2015

Briefing Paper

Negative Impacts of the Lower Sesan 2 Dam on Cambodia
The Lower Sesan 2 Dam (LS2), currently under construction, is expected to bring not only enormous
negative impacts on the Sesan and Srepok Rivers in northeastern Cambodia, but also a disaster to theentire nation of the Royal Kingdom of Cambodia and Lower Mekong. To prevent this, we urge theGovernment of Cambodia to immediately order the project developer to halt the construction, disclose allrelevant information, and carry out a more comprehensive Environmental Impact Assessment (EIA), while
ensuring participation of all stakeholders, especially the affected local communities, and seriously
reconsider the project.
Major negative impacts to emerge:
1. LS2 will block fish migration between the mainstream Mekong River and the Sesan/Srepok Rivers.
At least 78,000 villagers living upstream of LS2 will lose access to migratory fish (Baird, 2009).
Reduction of these villagers’ protein intake will become a serious matter. LS2’s negative impacts
will also be felt in the Tonle Sap Lake as well as the entire Lower Mekong Basin. According toMekong River Commission (MRC), fishery population in the Tonle Sap Lake amounts to more than
1.2 million.
2. Claimed economic benefits are questionable as electricity generation can fall significantly in thedry season. A simple comparison between the anticipated revenues from LS2’s electricity
generation and the loss of fish production suggests that the latter can be much larger. While LS2 is
expected to raise the revenue of about 29.58 million USD each year (IR, 2014), the total value offish production only along the Sesan River ranges from 1 to 25 million USD (Baran et al., 2013: 16).
3. The water quality along the Sesan and Srepok Rivers will be degraded as LS2’s reservoir will holda large amount of water and release it when generating electricity. The water quality degradation
will cause health problems to the local communities who depend on the river water.
4. LS2 could reduce the basin’s sediment load by 6.0 to 8.0%. Not enough nutrients will be delivered
downstream, affecting the ecosystem of the Mekong River, including the Tonle Sap Lake (IR,2014). The fertile water and productive soil to be used for agriculture will also be lost.
5. A number of local communities living along the Sesan and Srepok Rivers have lodged strong
oppositions to LS2. Their voices should seriously be heard. Otherwise, dissatisfactions anddistrusts towards policy makers among these villagers may emerge.

Background of the Project:
LS2 is being under construction on the Sesan River in Sesan District, Stung Treng Province. It is
located 1.5 km downstream from the Sesan River’s confluence with the Srepok River. The project wasapproved by Cambodia’s Council of Ministers in November 2012. The construction commenced in February2014.
LS2 is proposed to generate electricity, with installed capacity of 400 MW. The planned dam height is
40 m from the river bed and the length is 8 km. The dam will flood 33,500 ha of land. These information is1

M ek on g Wat ch
3 F A o k i B u i l d i n g 1 - 1 2 - 11 Ta i t oTa i t o - k u , To k y o 11 0 - 0 0 1 6 J a p a n
E-mail: info@mekongwatch.org
W e b s i t e : h t t p : / / w w w. m e k o n g w a t c h . o r gbased on the 2008 EIA (Key Consultants Cambodia, 2008). However, more detailed and updated design
information on the project has not been disclosed to the public, which makes the verification of anticipatedenvironmental and social impacts extremely difficult.
The developer of the LS2 project is the Hydro Power Lower Sesan 2 Company. It is a joint venture
among Cambodia’s Royal Group (a 39% shareholder), China’s Hydrolancang International Energy, asubsidiary of Huaneng Group (51%), and EVN International Joint Stock Company, a subsidiary of theElectricity of Vietnam (EVN) (10%).
References
Baird I. G. 2009. Best practices in compensation and resettlement for large dams: The case of the planned lower Sesan 2hydropower project in northeastern Cambodia. The River Coalition in Cambodia, Phnom Penh: Cambodia.
https://www.academia.edu/1049246/Best_Practices_in_Compensation_and_Resettlement_for_Large_Dams_The_Case_of_
the_Planned_Lower_Sesan_2_Hydropower_Project_in_Northeastern_Cambodia
Baran, Eric et al. 2013. Fish and fisheries in the Sekong, Sesan and Srepok Basins (3S Rivers, Mekong Watershed), withspecial reference to the Sesan River. Mekong Challenge Program for Water and Food Project 3: Optimising cascades ofhydropower for multiple use. International Centre for Environmental Management.
http://www.optimisingcascades.org/wp-content/uploads/2013/11/F_E-2.-Fish-and-fisheries-in-the-Sesan-river-basin.pdf
Inland Fisheries Research and Development Institute. 2013. Food and nutrition security vulnerability to mainstreamhydropower 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 andDevelopment Institute, Fisheries Administration, Phnom Penh: Cambodia.
https://www.oxfam.org.au/wp-content/uploads/2014/02/pdf_food-and-nutrition-for-print-2.pdf
International Rivers. 2014. Starving the Mekong: Expected social and environmental impacts from construction andoperation of the Lower Sesan II Dam. California: International Rivers.
http://www.internationalrivers.org/files/attached-files/starving_the_mekong_2.pdf
Key Consultants Cambodia. 2008. Environmental impact assessment for feasibility study of lower Sesan2 hydropower project,
Stung Treng province, Cambodia. Power Engineering Consulting Joint Stock Company1-Vietnam and Key Consultants
Cambodia.
Ziv, G. et al. 2012. Trading-off fish biodiversity, food security, and hydropower in the Mekong River Basin. Proceedings of theNational Academy of Science 109.15: 5609-5614.
http://www.pnas.org/content/109/15/5609.full

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