Green algae is unusually blooming in the drying Mekong river in Loei province. Credit: Chaiwat Parakun

Mekong locals observe changes in the Mekong following upstream dam operations

Jinghong dam in China’s Yunnan province continues cutting water outflows for its power grid maintenance through the second week while downstream has reported changes in the river, ranging from water fluctuations, sharp drops of water levels, algae blooming, and others. The Xayaburi dam further downstream, meanwhile, remains silent

Mekong residents from Northern districts like Chiang Khong down to Northeastern provinces like Loei and Nong Khai have reported unusual changes of the river over a week or so after Jinghong dam adjusted its water outflow regulation by cutting the discharge down by almost half for power grid maintenance, starting from January 5.

Chiang Khong residents were among the first to feel the disruption at the beginning as the water levels of the river flowing through the district and Chiang Saen nearby dropped sharply by over half a meter.

The phenomenon was confirmed by the Mekong River Commission (MRC), which saw the water drop, measured at its first monitoring station on the river in Thailand in Chiang Saen during January 2 to 4, from 2.85 to 1.90 meters, or almost a meter already (0.95 m). 

The water level was then slightly up, around 20 cm. or so, from January 5 to 11. The Office of National Water Resources (ONWR) also reported the drop during the same period by around 60 cm.

The drying Kok tributary in Chiang Rai.
Credit: The Network of Thai People in Eight Mekong Provinces

The residents also reported unusuality in the tributaries as they too were drying up. The residents, led by Raksa Chiang Khong group, had surveyed the areas, and they suspected that the drop of the water levels in the mainstream river was drawing the water outflow of the tributaries. This, they said, could affect the tributaries’ ecosystems.

In Loei and Nongkhai provinces in the Northeast, where the Mekong sneaks back to the Thai territory again, the water in the river is reportedly unusually drying up, exposing some riverbeds in the river.

Chaiwat Parakun, a member of The Network of Thai People in Eight Mekong Provinces, said the water level in the river has dropped over the last few days, over 30 cm. That prompts the blooming algae to be drying up and has started to cause a problem to fishers as it is floating around and has got stuck in their fishing gears.

The blooming algae itself is unusual, Mr. Chaiwat said, adding the phenomenon occurred since late last year when the river turned crystal clear as sediments were trapped upstream, and the weed now is too redundant.

The drying up algae, he added, is not good to the fish either because the weed provides a nursery ground for some fish. It’s now suddenly drying up, and the fish finds no place to lay eggs. 

“I think the ecosystem is being disrupted severely, and this is critical,” said Mr. Chaiwat.

However, he said the locals could hardly do anything about this as the causes of the problem are too complicated. So far, nobody is told clearly about the role of the Xayaburi dam, which is the closest to the provinces, around 200 kilometers away.

Nong Khai residents Somjit Pimpopan, who also helps collect data for the locals’ riverine research, said the locals’ riverside gardens are also being affected. The residents have to draw water from the river using a water pump.

The river section in Chiang Khong, where sandbars and rapids emerge out of the shallow water.
Credit: The Network of Thai People in Eight Mekong Provinces

Power grid maintenance

While the operation of the Xayaburi dam, the first dam on the Lower Mekong section in Lao’s Xayaburi, has not been publicly disclosed, Jinghong dam upstream has notified the countries downstream about some temporary adjustment of the dam operation.

According to the ONWR’s Secretary-General, Somkiat Prajamwong, the Water Resources Ministry of China sent the notification to the office dated January 5, informing that the dam would reduce the water discharge, from 1,904 cu m per second to 1,000 cu m per second during January 5 to 24 for power grid maintenance. The dam would resume its normal operation afterwards, it noted.

Following the notification, the ONWR projected the impacts on water levels in Thailand’s section, saying the river level in Chiang Saen would drop around 30 cm during the period. The water, it noted, had dropped around 60 cm during January 2 to 4 already.

Further downstream of the Xayaburi dam, which means provinces like Loei, Nong Khai, down to Ubon Ratchathani, the water levels would also drop by 30 cm, but these also depend on the operation of the Xayaburi dam, the office noted.

The office then issued a warning to those provinces to prepare themselves for possible disruptions.

The MRC had also received the notification from China’s ministry on January 5, stating that the “maintenance of transmission lines of the power grid” would result in water outflow reduction at 1,000 cubic meters per second from January 5 to 24.

The notification further noted to the organization that the amount of water flow would be gradually restored to its normal operation status on January 25. However, the MRC said the ministry did not specify the river level before the reduction or the volume to be restored on January 25.

Credit: MRC

Based on the MRC’s observed water level data at Jinghong available until January 4, it showed that the outflow level started decreasing from 1,410 cu m per second on December 31 to 768 cu m per second a day later, representing an almost 50% drop. The flow just rose slightly, around 20 cm, to 786 cu m per second over January 1 to 4, the MRC noted.

As a result, the MRC concluded that the water levels along the Mekong River were likely to drop by about 1.20 m, based on its observed and forecasting water level data.

It also warned the river residents downstream through its press release of possible impacts.

“Navigation activities on the Mekong River, especially around the areas close to Jinghong, may be affected more than the other places during this period. Some local livelihood activities such as river weed harvesting and fishing may also be affected,” said Dr. Lam Hung Son, Head of the MRC Regional Flood and Drought Management Centre.

Under an agreement between China and the MRC, China pledged to notify the MRC and its Member Countries of “any abnormal rise or fall in water level or discharge, and other information on factors that might lead to sudden flood”, the MRC noted.

In its weekly situation report from January 5 to 11, the water level at Chiang Saen slightly increased around 20 cm, from 1.87 to 2.07 m. 

The water level at Chiang Khan in Loei province, meanwhile, decreased around 1. 20 m, from 4.93 to 3.76 m during this week, and this almost 90 cm below its long-term average level.

Downstream water levels from Vientiane to Paksane in Lao PDR also decreased, varying up to 35 cm.

The water levels at Nong Khai and Paksane are lower than their record last year and even lower than their historical minimum levels. Water levels at Nong Khai and Paksane are considered “very critical”, the MRC noted.

The crystal clear Mekong in Pakchom, Loei province.
Credit: The Network of Thai People in Eight Mekong Provinces

Seasonal cycle

 While the information regarding water discharge from Jinghong dam varies among informed agencies, Niwat Roykaew, chair of the Raksa Chiang Khong group said it cannot be denied that the impacts are caused by the dam.

The MRC’ data has shown how the water levels in the Mekong dropped since the beginning of the year, and this is in line with residents’ observations, he said.

Such a sudden disruption has reflected that river management still serves economic development, whereas the Mekong has various aspects to consider, including people’s livelihoods. 

China’s notification and data sharing, therefore, is not enough to manage the river, Mr. Niwat stressed.

The current river management is not in line with a seasonal cycle, and this prompts disruptions to the river’s ecosystems and people’s livelihoods. 

“The river needs to be managed following its seasons and ecosystems. This is the most critical fact to bear in mind,” said Mr. Niwat.