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New scientific study: Dams on Sesan River polluting water and poisoning downstream communities September 10, 2009

Posted by chandrapong007 in Environment.


8th September, 2009

New scientific study: Dams on Sesan River polluting water and poisoning downstream communities.

3S Rivers Protection Network logoAddress: PO Box 89007, Village 4, Banlung Town, Ratanakiri,
tel: (855) 75 974 112
Email: sesan@online.com.kh

Ratanakiri Province, Cambodia – A new report has linked upstream hydropower reservoirs to high levels of toxic algae and bacteria found in the Sesan River, which exceed World Health Organisation (WHO) limits for safe drinking water.

Adverse environmental and social impacts caused by hydroelectric damming of the Sesan River are reflected in a report released by STRIVER; a research strategy for improved water resource management jointly coordinated by the Norwegian Institute for Agricultural and Environmental Research (BIOFORSK) and the Norwegian Institute for Water Research (NIVA). The report illustrates how detrimental dams on the Sesan River in Vietnam have been to the quality of water in the Sesan River and the health problems faced by communities living downstream in Ratanakiri province, Cambodia.

These research findings are especially relevant given proposals are in place to construct 5 dams on the Sesan River and its tributaries in Cambodia, including the large 400MW Sesan II dam in Stung Treng, which is anticipated to resettle over 5,000 people, inundate more than 33,000 ha of land, and have large scale impacts on fisheries and the livelihoods of both upstream and downstream communities.

The 2009 STRIVER technical brief entitled “A limnological study of the Sesan River in Cambodia in the dry season: focus on toxic cyanobacteria and coliform bacteria” is based on scientific research carried out by Anna Madeleine Tiodolf, Norwegian University of Life Sciences with field assistance provided by the 3S Rivers Protection Network (3SPN). The report presents the results of a water quality study conducted during the dry season over a two-week period in March 2008 in which water samples were taken in two different locations along the Sesan River in Ratanakiri province; Andong Meas, 30 kilometres downstream of the Vietnamese border, and Vuen Sai, 130 kilometres downstream of the Vietnamese border.

The study confirmed the occurrence of cyanobacteria and cyanotoxins in the Sesan River mainstream, however no cyanobacteria were detected in the water samples taken in three different tributaries, indicating the polluted water to originate from a more stagnant mainstream source such as an upstream hydropower reservoir.

The water is not suitable for human consumption

Research by Tiodolf found concentrations of toxic algae (cyanotoxin) and presence of the indicator species E.coli, coliform bacteria, in the Sesan River exceed World Health Organisation (WHO) limits for safe drinking water.

Cyanotoxins are cancerous to the liver after longer periods of exposure, while excessive levels of E.coli concentration are commonly associated with many health problems and present an increased risk to communities through the spreading of waterborne disease.

Results are consistent with the gastric disorders and skin problems experienced by Sesan River communities since the construction of the Yali Falls dam. Approximately 28,000 people rely on the Sesan River for their drinking water, fishing, bathing, and feeding livestock and according to a report prepared by the Fisheries Office in 2000 entitled “A study of the downstream impacts of the Yali Falls dam in the Sesan River Basin in Ratanakiri Province, Cambodia.” The 2000 report stated that 952 people had died along the Sesan River, with large numbers of domestic animals, as a result of diseases believed by local communities to be directly associated with the Yali Falls dam.

A 2007 Environmental Impact Assessment (EIA) report on the Sesan River similarly identified toxic algae as the likely reason for villagers’ illnesses. The EIA report prepared by the Norwegian Institute for Water Research and Nordic hydropower consultants, SWECO Grøner, confirmed that there are strains of toxin-producing cyanobacteria present in the Yali Dam Reservoir, and that water quality in the Sesan River has “seriously deteriorated since the construction of the Yali Power Plant” with the cyanobacteria producing “exactly the same symptoms” as reported by Cambodians downstream.

Mr. Meach Mean, Coordinator of the 3S Rivers Protection Network which works with communities along the Sesan River in Ratanakiri, indicates that this study confirms what villagers have been reporting for years. “The research by STRIVER clearly demonstrates the disastrous ecological and social effects large dams can have on rivers and the associated health problems for downstream communities. We hope this report will help initiate remedy for the communities who have been waiting for mitigation and compensation from the past and present impacts of Vietnam’s dams”.

Construction on Vietnam’s Yali Falls dam began in 1993 by the Electricity of Vietnam on the Sesan River and is located approximately 70-80 km from the border of Cambodia. Since its construction and operation in 2001, villagers living downstream have experienced large-scale social, economic, and environmental impacts. Despite complaints and requests from communities for mitigation no solution has been forthcoming

Mr. Say Duen, from Koh Peah Commune, in Vuan Sai district confirmed that health problems started approximately 5 to 10 years ago. “When we use the river water to cook, or to wash, we sometimes get a skin rash or diarrhea, and children who swim and drink the water get sick, especially during the dry season. I hope that this message will be received by the government and dam builders and they use their responsibility to find a solution for our people.”


For more information, photos, or documents mentioned in this press release:
Contact: Mr. Meach Mean, Coordinator, 3S Rivers Protection Network, sesan@online.com.kh, +855 (0)11 758 970.

The 3S Rivers Protection Network (3SPN) is a civil society organisation representing indigenous people living along the Sesan, Srepok (and Sekong) Rivers in Cambodia.



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