Authorities have been doing too little to regrow trees they felled to make way for hydropower projects, experts said.
Growing trees is the most effective way to control floods and prevent erosion in downstream areas, Dao Xuan Hoc, chairman of the Vietnam Water Resources Development Association, said at a conference in Hanoi on Wednesday. VNExpress, a local media reported.
Trieu Van Hung, chairman of the Vietnam Forest Science Technology Association, said it has been done in quantity rather than quality.
When trees are planted, they are not chosen well, he said, pointing to the fact that at some places trees that do not prevent erosion such as gum and acacia and those with short lifespans are grown.
“The forests that are cleared for dams are natural forests, and they took a long time to form those canopies and ecosystems.
“There are no specific guidelines for the types of trees or growing methods for the reforestation process, and therefore it is difficult to recover the biodiversity and environment that have been lost.”
There should be a ban on felling natural forests, protective forests and special use forests, including to build dams, he said.
Other experts at the event too voiced concern about the impact of dams on the environment.
Large amounts of sediments are trapped in reservoirs rather than flow downstream, affecting agriculture, they said.
It also changes the flow of rivers and causes riverbank and coastal erosion and lower riverbeds.
Hoc suggested building larger spillways in dams for discharging water, and having specific plans for discharge during the dry season every year.
He also said it is necessary to mandate that the volume of water discharged does not exceed the inflow into reservoirs.
As of 2018 the country had 385 operational hydropower projects with another 143 under construction, according to state-owned power distributor Vietnam Electricity.
By Nguyen Xuan