Mekong water levels in the Northeast reach their peaks today whereas some areas are submerged

Rainfall in the aftermath of Typhoon Yagi has also left impact on communities along the Mekong River as excess water from tributaries has been running into the mainstream river, prompting water levels in several locations to increase close to or above flood level

The Office of National Water Resources (ONWR) has warned that water levels in the Mekong River in the Northeast will reach their peaks today. ONWR’s Secretary-General Dr. Surasee Kittimongkol said the office has been monitoring the situation alongside the Mekong River Commission Secretariate (MRCS) and learned that the water level in the Mekong River at Chiang Saen station in Chiang Rai province was reported to have reached its peak yesterday whereas the water levels downstream in the Northeast, from Chiang Khan in Loei province to Nong Khai province, will reach their peaks today, increasing by around 40 cm.

As reported by the ONWR today, the water level at Chiang Khan will increase between 0.5 to one metre, resulting in the level above flood level by 0.2 to 0.8 m. In Nong Khai and Bung Kan provinces, the water level will increase between 1.25 to 2 m, resulting in the level above flood level between 0.7 to 1.65 m.

l The risk assessment and detailed mapping of the flooding in Nong Khai province based on the peak of the Mekong water level on Sep 15 by Assoc. Prof. Dr. Seree Supratid and ESRI. Credit: Assoc. Prof. Dr. Seree Supratid FB Page

They submerged under floodwaters two days ago or Sep 13 alongside Vientiane of Lao PDR. Further inland in Sakon Nakhon and Udon Thani provinces, the water levels may increase above flood level by 30 cm in the next four days.

The MRC also issued a warning today, saying Vientiane and Nong Khai are still at flood level. In Nakhon Phanom further down, the water level has just reached alarm level and Paksane in Laos is 0.2 m approaching alarm level. The situation in Chiang Khan is projected to return to normal condition in the next four days, or Sep 19. The water level in Vientiane, which is being flooded, will reduce to alarm level in the next two days, or Sep 17. 

In Nongkhai, the water level will remain at flood level until Sep 18 while Paksane will reach alarm level in the next two days or Sep 17. Luang Prabang, which had been under floodwaters since Sep 11 by one meter, meanwhile, is expected to return to normal today.

Tomorrow and the day after, isolated heavy rainfall is forecasted in the central part of the Lower Mekong Basin. Isolated very heavy rainfall is forecasted in the Northeastern part of Thailand and the Northern and Northeastern parts of Cambodia, the MRC noted.

Did upstream dams exacerbate the situation?

Overflows of the Mekong River are highly speculated to have resulted from the releases of water upstream from China’s dams, but concerned agencies have ruled this speculation out so far, citing the dams upstream were operated almost at the same regular protocol prior to Typhoon Yagi.

According to the MRC, which reported on Sep 13, the water level at Jinghong Hydrological Station, China is almost stable ranging from 535.65 to 535.58 m (above sea level) within the past three days. It said there was no indication from China that Jinghong dam would make any major release in the immediate future.

The US-based Mekong Dam Monitor, which monitors dam operations and protocols in the Mekong region, has shared similar observations. 

“This is not a matter of being friendly to China or friendly to another country. Science knows no boundaries. We let the data speak itself and use science to provide accurate information to people who need it,” Mr. Brian Eyler, co-leader of the MDM and Director of Stimson Center’s  Southeast Asia Program and the Energy, Water, and Sustainability Program, posted on the organisation’s FB Page a few days ago.

Mr. Eyler explained to Bangkok Tribune that the Yagi floods are bigger and even more unpredictable than the floods from three weeks before in northern Thailand. Some are calling this a 30-year flood and others have said the Mekong hasn’t flooded like this since the 1960s.

The MDM has been monitoring dam operations throughout the basin over this critical time. Regarding China’s dams at the moment, it has found that there is absolutely zero evidence that those dams made flooding worse during the floods three weeks before and during the Yagi floods.

Prior to Yagi, China’s Jinghong dam lowered its reservoir level by 4-5 meters without increasing outflow, likely in preparation for Yagi’s incoming waters, his organisation noted. The Jinghong dam did not increase outflow over the week of Sep 1-7, according to the MRC Jinghong gauge. So, the Jinghong Dam had zero effect on the rising Mekong River levels in Chiang Rai province.

Mr. Eyler explained that in other words, it discharged water out but at a constant rate and at the same rate prior to lowering the reservoir. So, the river level did not go up as it discharged water. This was done with coordination from upstream dams too. 

From Sep 6, onward discharge from the Jinghong dam has only decreased over time, which means it’s likely filling up. Because it lowered its reservoir 4-5 meters the week before and now it’s filling up again.

“But we know Yagi is raging over Jinghong so the river should be going up. The gauge is not going up, so that means the dam must be filling, pointed out Mr. Eyler.

The MDM estimates the Jinghong dam released around 240 million cubic meters around Sep 6 in preparation for Yagi, dropping its reservoir by four meters. However, since the river level downstream in Jinghong did not increase, this release did not have a negative effect on the downstream and could only have been done in this manner with coordination from upstream dams.

Mekong tributaries

On Sep 12, the MRC relayed a statement issued by the Lancang-Mekong Cooperation (LMC), suggesting that Jinghong dam lowered its operation and reduced the outflow from 1,800 cu m/s on Sep 1 to 1,060 cu m/s, or 70% compared to its average flow. It further said the dam will not release water through spillway gates, and the outflow is expected to remain at the current level.

The MDM has also been monitoring the situation in the Mekong tributaries. In Luang Prabang, which was experiencing a severe flooding event, the organisation noted that it was unclear the degree to which the dams on the Nam Ou and Nam Khan River have helped or exacerbated the flooding around Luang Prabang. The MDM further noted that dams on both rivers performed emergency drawdowns prior to Yagi and this caused early flooding in low lying communities downstream even before Yagi hit. 

As such the Xayaburi dam downstream from Luang Prabang needs to be able to clear the incoming floods fast enough so that floods do not back up into Luang Prabang. 

“We are watching dams in Laos, and we are particularly watching whether the Xayaburi Dam can clear the massive inflow to prevent catastrophic flooding at Luang Prabang. This will be the first big test of the Xayaburi Dam’s ability to pass a massive flood event through its structure,” said Mr. Eyler in addition.

The MDM noted that it is becoming apparent that the use of dams for flood control purposes in this part of the Mekong is just a myth. Dams are introducing more risks and more uncertainty to vulnerable communities.

Any dam bursting on Myanmar’s tributaries?

The Yagi food incident also caused speculation on social media that an upstream dam in Myanmar had burst and caused the extreme flooding in Chiang Rai. The storm caused severe flooding in tributaries of the Mekong in rivers like Ruak and Kok, which run from Myanmar into Thailand. In Chiang Rai, the Kok River rose incredibly fast on Sep 1.

However, satellite imagery from the MDM proves that there are no upstream dams in Myanmar on the Kok River. The MDM cautioned that this social media messaging was misinformed. The speculation was happening because reliable and accurate information was not being provided to people in need along the Mekong, the organisation noted.

“Yagi clearly underscores a need for more effective transboundary early warning systems and improved anticipatory action programming both from the Thai government and international disaster response organizations. The same is needed in Laos where people in need have even less information and less preparatory capacity to be safe from harm,” the MDM remarked.