The water outflow at Jinghong hydropower station in China’s Yunnan province is dropping due to power grid maintenance during 5 – 24 January, leading to changes in river water levels along the Mekong River in Thailand, Lao PDR, and Cambodia, according to a press release from the Mekong River Commission.
According to a notification from China’s Ministry of Water Resources that the Mekong River Commission Secretariat (MRCS) received on Jan. 5, the “maintenance of transmission lines of the power grid” will result in water outflow reduction at 1,000 cubic meters per second (m³/s) from 5 to 24 January.
The amount of water flow will be gradually restored to its normal operation status on Jan. 25, the notification said. However, the ministry did not specify the river level before the reduction or the volume to be restored on 25 January.
Based on the MRC’s observed water level data at Jinghong available until 4 January, the outflow level started decreasing from 1,410 m³/s on 31 December, 2020 to 768m³/s on 1st Jan. 1, 2021, representing an almost 50 percent drop. But the flow rose slightly to just 786 m³/s over 1 to January.
As a result, water levels along the Mekong River are likely to drop by about 1.20 metres, according to MRC’s observed and forecasting water level data.
In Chiang Saen–the first monitoring station on the Mekong River in Thailand located approximately 300 kilometres away from Jinghong –the water already dropped by about 2 metres during 2 and 4 January. The level is expected to slightly increase up to 0.05 metres during 5 and 11 january.
The stretches from Vientiane to Paksane of Lao PDR, including Nongkhai of Thailand, will experience a drop of 0.22–0.35 metres in their water levels during 5 and 11 January.
In the Mekong mainstream from Thailand’s Nakhon Phanom, Mukdahan and Khong Chiamto Lao PDR’s Thakhek, Savannakhet and Pakse, the water levels will fall slightly less, varying between 0.03 and 0.15 metres between 8 and 11 January.
In Cambodia, the water levels along the Mekong in Stung Treng, Kratie, Kampong Cham, Phnom Penh, Koh Khel and Neak Luong did not see any apparent decrease yet until 5th January. The river level at these locations is expected to not change significantly, only dropping between 0.03 and 0.07metres during Jan. 9–11.
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, adding that the Centre will continue to monitor the situation closely.