Hydropower plants worsen central Vietnam flooding

Over the past few days, downstream areas of the Ba Ha River in the south central province have been flooded due to heavy rains and upstream hydropower plants opening their floodgates and discharging water in high volumes.

Many people say the floods came too quickly and the plants failed to inform them in time.

Tran Ly, general director of the Ba Ha River Hydropower Joint Stock Company, said the Central Highlands region has been experiencing heavy rains over the past few days, prompting two hydropower plants upstream the Ba Ha River plant to open their floodgates, resulting in water rushing down at 10,000 cubic meters per second.

As the Ba Ha River plant is the last one downstream, it is forced to open its floodgates as well, Ly explained.

Last Tuesday, the Ba Ha plant raised its released water volume from 4,000 m3/s to 9,000 m3/s over seven hours, an accumulated volum of tens of thousands of Olympic swimming pools.

It had to do so to control water levels in its reservoir after two other plants upstream had opened their floodgates, he said.

Ly admitted that the release of high volumes of water has exacerbated flooding in downstream areas. He said the opening of floodgates is decided by the provincial People’s Committee, which also has the responsibility of informing residents about it.

He said the company has made a record of people impacted by the floods this time as reference for future actions.

Tran Huu The, chairman of the Phu Yen People’s Committee, said there were heavy rains in the province on Tuesday. This, coupled with the fact that the Dak Srong and Krong Hnang hydropower plants released water volumes at 10,000 m3/s, made it imperative for the Ba Ha plant, whose reservoir can only hold 150 million cubic meters of water, to open its floodgates.

Authorities have also instructed the Ba Ha plant to release water appropriately depending on tide levels to ensure the least impacts on downstream areas, he said.

On November 30, the Hinh River and the Ba Ha River hydropower plants released water volumes of around 6,000 m3/s, increasing the rate to around 9,000 m3/s at noon and 11,000 m3/s at around 3 p.m. Water was released more slowly after 4 p.m. at around 6,400 m3/s and stayed at that rate until the next morning.

"We knew the tide was highest starting from 7 p.m., so we regulated the water volumes flowing downstream, preventing big floods at night which could be very dangerous," said The.

For now, localities will try to mitigate the impacts of rains and floods and help people return to their daily lives. In the long run, many smaller reservoirs would be needed to store water for the dry season and lessen flooding impacts during rainy seasons, he added.

In the past five days, heavy rains and floods have inundated many houses in Phu Yen and forced the evacuation of tens of thousands of local residents.

At least 18 people have died or gone missing in central and Central Highlands during this period.