The Sesan, Srepok and Sekong (3S) rivers basin is a major tributary and watershed of the Mekong River and is located in the countries of Vietnam, Cambodia and Laos. Throughout Cambodia and Laos many people live close to river systems and are highly dependent on the rivers' rich natural resources for their survival. The 3S basin supports nearly 3.5 million people, many of whom are ethnic minorities.2 The area has been recognized for its biological importance due to its rich aquatic and terrestrial ecosystems, with over 20 percent of the basin currently designated as protected areas, including the Lumphat Wildlife Sanctuary and the Virachey National Park in Cambodia. Many of the basin's deep pools have been recognized as Fish Conservation Zones, as the three rivers support diverse fish and aquatic resources. Studies have identified more than 133 fish species in the Sesan, 204 species in the Srepok and 214 species in the Sekong.3

The majority of the 3S region's people depend on fishing, agriculture and collecting non-timber forest products (NTFPs) for their livelihoods4 - for many thousands of people, the health of the rivers is central to their survival. However, recent years have seen an emphasis on developing large-scale hydropower along all three rivers, which threatens to drastically alter the ecology of the area and is likely to have devastating impacts for those whose livelihoods are connected to the basins' resources. The construction and operation of 20 large hydropower dams in the upper stretches of the 3S rivers in Vietnam has already had severe negative impacts on local communities in Cambodia through decreased fish stocks, erratic water fluctuations, and reduced water quality, which combined have made it more difficult for people to meet their daily food and income needs.5 There is growing pressure to construct more than 26 new hydropower projects in the 3S basins, threatening large lengths of the river which are still largely intact. If built, these dams will alter the basin's natural resources through changes in the region's water flows and quality, land use and forest cover, and would block important fish migration routes and change aquatic habitat required for the migration, spawning and feeding of fish. This in turn could disconnect people from their traditional livelihoods and forms of resource management, which would have serious economic and social implications on future environmental sustainability, landscape quality and biodiversity.

Until recently the majority of the 3S region's hydropower plants were concentrated in Vietnam along the upper reaches of the Sesan and Srepok rivers, and most were developed by the Vietnamese state power company, Electricity of Vietnam (EVN). More recently, new projects have been proposed in Cambodia, and the pace of approval and construction of dams in southern Laos has also picked up pace. In addition to EVN involvement there are now new actors moving into the sector, including Chinese state-owned companies and private enterprises from Korea and Russia. International financial institutions have become important players in the bigger picture of regional power sharing, with the Asian Development Bank and the World Bank committing significant funds to supporting the construction of high voltage transmission lines, with the eventual aim of creating a regional power grid. Plans are already underway in the 3S area to connect proposed hydropower plants to these transmission lines.

Bathing in the Sesan River. Photo: Oxfam-Brett Eloff

A number of studies have been conducted into the impacts of the area's existing dams, which have raised a number of serious concerns regarding their negative impacts on the environment and local communities. For more than a decade, these reports have documented how downstream communities on the Sesan River, and more recently on the Srepok River, in Cambodia have suffered from a cascade of seven dams built upstream in Vietnam. As many of the riparian communities in the region depend upon the river's fisheries and surrounding natural resources for their livelihoods and food security, the development of hydropower has increased poverty and hardship for many of these communities, due to depleted fish stocks, erratic water fluctuations and worsening water quality. Despite these well documented impacts, communities in Cambodia have never received remedy for the hardships experienced as a direct consequence of Vietnam's upstream hydropower activity.

Despite the impacts identified in the planning, approval and implementation of existing hydropower projects in the 3S area, there are concerns that the same mistakes are set to be repeated. As illustrated in this report, the push to approve and develop projects continues to take priority over serious analysis of the full impacts of individual projects, and there is an almost total absence of serious consideration of the cumulative impacts that the more than 46 hydropower projects are likely to have on the region. This lack of adequate analysis is exacerbated by the fact that hydropower planning and development continues to be considered a sensitive issue in the basin, consultation with affected communities is generally poor, and detailed and reliable information often inaccessible.

The effect of this lack of transparency is that those most likely to be impacted by these developments have very little awareness of the potentially life changing decisions that are currently being made without their input. Not only are communities in the dark about plans for the area, civil society and development partners working on community development, livelihood improvement and environmental protection remain unaware of how their projects are likely to be affected. Staff from the government's technical agencies, such as the fisheries and forestry administrations, are also beginning to quietly voice their own frustrations at not being adequately consulted in the study and approval of these projects.

In order to better understand the challenges confronting the region's natural resources and its people, there is a need to identify and analyse the changes currently occurring in terms of the actors involved, the factors driving new developments, and the trends occurring throughout the hydropower planning and approval process. Once the new challenges confronting the region are better understood, civil society will be able to understand how to better engage with these new actors and provide more effective responses to the problems faced. For the most part focussing on Cambodia, this report aims to explore the actors involved in projects affecting the 3S rivers, and what factors are driving hydropower expansion in the area. It provides updates on the largest and most advanced projects proposed and the main impacts that can be expected to result from increased hydropower development in the basin. It is hoped that the report will fill crucial information gaps and promote discussion amongst all stakeholders, including affected communities and the wider Cambodian population, government and decision makers, project developers, and civil society.

2 3S Rivers Protection Network (3SPN), Civil Society's Reflection of Past and Present Hydropower Development in the 3S Rivers Basin Paves Concern Over Future Development Plans, 31 May 2010.

3 ADB-RETA 40082, 3S Technical Sheets Key Topic 5 - Biodiversity and natural resources. docman&Itemid=184&lang=en (accessed November 2011).

4 ADB-RETA 40082, 3S Technical Sheets Key Topic 7 - People and livelihoods, 8a Hydropower Development. (accessed November 2011).

5 Rutkow, E. et al. Down River: The Consequences of Vietnam's Se San River Dams on Life in Cambodia and Their Meaning in International Law. NGO Forum Cambodia, December 2005.