Residents say upstream water release caught them by surprise, despite reports Cambodia was notified by Vietnamese authorities
VILLAGERS living along the Sesan River in the country's remote northeast have experienced a sudden surge in water levels brought on by releases from a hydropower dam upstream in Vietnam, according to environmental activists.
On February 8, three villages in Ratanakkiri province's Vuen Sai and Andong Meas districts reported a one-metre rise in the level of the river, which became "unusually turbid", according to a statement released Tuesday by the Sesan, Srepok and Sekong Rivers Protection Network (3SPN).
Provincial 3SPN coordinator Kim Sangha said the surge had been caused by tests at the newly completed Sesan 4 dam in Vietnam's Gia Lai province, but that local residents had received no advance warning from the authorities.
"I visited two places and people said the same thing: They didn't know when the water will be released," he said by phone from Banlung.
"The dam is testing its flow and is not notifying the local people."
Kim Sangha said the Cambodian government was notified by Vietnamese authorities last month that water releases would occur in February, but that the Cambodian National Mekong Committee (CNMC) had apparently failed to pass the information on to affected areas.
"I think there are problems transferring the information from the national level to the provincial level, and then onto the local level," he said, adding that, although there were no deaths, the water rises had alarmed local villagers.
"If the water comes up too quickly, people may not be able to escape. That is our worry."
But CNMC Secretary General Pich Dun said he did not receive notice of the water release, promising to follow it up with his colleagues in Vietnam.
He added that a Vietnamese regulator dam nearing completion on the border will soon allow the water to flow into Cambodia at a constant rate of 190 litres per second, preventing surges from upstream dams.
"They can regulate the water so that it will flow constantly," he said.
The 462-kilometre Sesan River, which flows from Vietnam's Central Highlands through Ratanakkiri province and into the Mekong mainstream at Stung Treng, has been heavily dammed by a Vietnamese government eager to alleviate local power shortages.
Environmental groups say this is only the latest case of a Vietnamese dam wreaking havoc downstream on the Sesan.
In 2002, International Rivers wrote that the operation of the 720-megawatt Yali Falls Dam had caused "rapid and daily fluctuations in the river's flow downstream in Cambodia's Ratanakkiri and Stung Treng provinces", resulting in 36 deaths from flash flooding.