Lao Dams, Mining Ruining Sekong Water Quality in Cambodia

3s-rivers-map-600.jpg A map showing Southeast Asia's 3S Rivers region.

Dam-building and gold mining in southern Laos are ruining water quality downstream on the Sekong River in Cambodia, where villagers are no longer able drink or use the water, according to an environmental group.

The activities undertaken by Lao and Vietnamese companies on the Sekong’s tributaries are making the river water muddy and full of silt, said Meach Mean of the Cambodia-based 3S Rivers Protection Network, which monitors environmental issues in the Sekong, Sesan, and Srepok rivers in the Vietnam-Laos-Cambodia border area.

Because of the sediment in the Sekong, villagers downstream in Cambodia’s Stung Treng province do not dare drink the water from the river and want the Lao government to address the problem, according to the group.

“For Cambodians, the important thing is that countries should not cause problems for other countries, whether through building dams or through dredging for gold,” Meach Mean said.

Currently, the muddy waters were being caused by construction work under way on the Xe Pian-Xe Nam Noy hydropower dam on the Nam Noy River, a Sekong tributary, Meach Mean said.

“The construction of the Xe Pian-Xe Nam Noy dam is causing the Nam Noy River… to become very silty,” before it flows into the Sekong, he said.  
The dam, which will produce electricity for export to Thailand after it is completed in 2018, is one of a dozen hydropower projects Laos has planned or under way on the Sekong and its tributaries, including a series on the Sekaman that had previously caused silt downstream.

The Sekaman dams had been a “serious cause” of water quality problems in Cambodia until work on the Sekaman 3 wrapped up last year and construction on the Sekaman 1 was suspended over the past year, Meach Mean said.

Dredging for gold

Now, dredging for gold on the river’s tributaries in southern Laos’s Attapeu and Sekong provinces has become a bigger issue than the muddiness caused by dam construction, he said.

“The main problem now is the dredging of the Xekaman and Xesou Rivers in Attapeu province and the Sekong River in Sekong province for gold by Vietnamese companies and Lao companies working with Vietnamese companies.”

The companies use backhoes to scoop up soil from streams and riverbanks, then extract the gold onsite using chemicals, which likely include mercury, he said.

“This obviously causes a lot of turbidity downstream,” he said, referring to a measure of how much particulate is suspended in the water.

Previously, dredging had been done by Chinese-owned boats in the Sekong River, but now the heavy machinery used by Vietnamese companies is causing more sediment to flow downstream.

Chemicals such as mercury are often used in the mining process to get gold out of rock, and residents in southern Laos have complained of toxic pollution from gold mining along the Sekong waters for years.

Sekong River Basin

Some 30,000 Cambodians and tens of thousands of Laotians—many of them members of ethnic minorities in both countries—live in the Sekong River Basin and rely on the waters for their livelihoods.

Environmental groups have said dams in the basin threaten fish stocks and sediment flows, with global green group International Rivers warning that little study has been done on what kind of long-term effects the dams will have on local communities.

The only large dam in full operation so far in the Sekong River Basin, the Houy Ho which was completed in 1998, proved “disastrous” for downstream communities in Laos and Cambodia, according to International Rivers.  

The projects are part of a “hydro boom” in land-locked, impoverished Laos, which has mountainous terrain suited to hydropower and is aiming to become the “battery” of power-hungry Southeast Asia by selling electricity to its neighbors.

Laos has come under fire from neighboring Cambodia and Vietnam for plowing ahead with construction on the Xayaburi dam, the first dam across the main stem of the Mekong River, over their objections.

The Sekong and the other 3S Rivers form important tributaries flowing into the 4,000-kilometer (2,500-mile) Mekong, Southeast Asia’s key artery.

'Little attention' to local communities

Earlier this month, two hundred environmentalists and riparian community representatives from Cambodia, Laos, Vietnam, Thailand, and southwestern China met in the Cambodian capital Phnom Penh to discuss how dams on the Mekong and the 3S rivers built by Laos and other countries were affecting their local river environments and living standards.

Tek Vannara, deputy director of the Cambodia NGO Forum that hosted the meeting, said regional governments including Laos “pay little attention” to local communities when making the decisions to build the dams.  

According to Laos’s Ministry of Energy and Mines, as of March Laos had 14 dams under construction across the country, 24 in the planning stage, and 32 in the feasibility study stage, in addition to 16 that had recently become operational.

Aside from selling electricity to its neighbors, Laos has also aimed to capitalize on its natural resources with mines, and its mining industry is growing fast.

According to the Ministry of Energy and Mines, there are currently more than 150 mining firms in Laos operating more than 200 mining projects.

Significant gold reserves have been found in Laos’s southern provinces, and the Ministry of Planning and Investment said recently that foreign investors are interested in exploring new gold, lignite, and silver mines near the Sekong and Sekaman rivers.

Reported by RFA's Lao and Khmer Services. Translated by Viengsay Luangkhot and Samean Yun. Written in English with additional reporting by Rachel Vandenbrink.


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