Mekong level rises as dam outflow returns to normal

Content image - Phnom Penh Post
Fishing boats sail the Mekong River in Phnom Penh’s Chroy Changvar district. Hean Rangsey

Water levels of the Mekong River have started increasing following a month-long drop precipitated by power grid maintenance at the Jinghong hydropower station in the Chinese province of Yunnan and compounded by lower rainfall, according to the Mekong River Commission (MRC).

The MRC Secretariat said on February 22 that water levels in some stretches of the Mekong had risen slightly over the previous seven days. Outflow at Jinghong station increased from 786 cubic metres per second (m3/s) on February 15 to 1,020m3/s on February 22.

Earlier this month, however, Chinese officials claimed that the outflow at Jinghong had been consistently over 1,000m3/s since the end of January.

The MRC said: “The discrepancy between outflow estimates may be due to the use of different methods to calculate discharges at the Jinghong station. The [MRC] Secretariat and China’s Ministry of Water Resources are now working together to provide more consistent water discharge information.”

On February 12, the MRC declared that Mekong water levels had dropped to “worrying” levels. It said the decline had begun at the beginning of the year due to lower rainfall, upstream flow changes, hydropower operations in tributaries, and outflow restrictions from the Jinghong dam.

The latest increase has been more apparent between Chiang Saen in Thailand and Vientiane in Laos but has been less perceptible between Thailand’s Nakhon Phanom and Laos’ Savannakhet, and between Cambodia’s Kampong Cham province and the Mekong delta in Vietnam, the MRC said.

China has agreed to share year-round hydrological data from two stations located on the upper Mekong – at Jinghong and at a tributary in Yunnan’s Manan, but the agreement covers data on water levels only – not discharges, the MRC said.

The MRC has forecast dry season weather this year to be wetter than the previous two years. This year’s monsoon season has also been forecast to begin in early May, rather than the usual start time late in the month.

In January, the Ministry of Water Resources and Meteorology issued a notice saying that weather conditions during the dry season and early in the rainy season this year were anticipated to be good.

Dry season temperatures might be around or slightly below norms, and the quantity of rainfall might be higher than usual. During March and April, there could be significant rainfall with storms and lightning strikes.

“There could be early seasonal rains, but the quantity of rainfall is expected to be much less than usage needs during that time. Please continue to conserve water and use it sparingly, especially in remote provinces far from water sources,” the notice said.

National Committee for Disaster Management (NCDM) spokesman Seak Vichet said NCDM leaders had ordered provincial officials and local authorities to keep water in storage for use as needed to meet development goals despite the beginning of the rainy season possibly coming early.