A part of the Dong Nai River in Bien Hoa City, Dong Nai Province. Scientists and experts have called for prompt actions to save the 610km river's flow and its ecology. — VNA/VNS Photo Sy Tuyen

The 610km river is believed to be the third longest river in the country, running through 10 provinces and HCM City and supplying water to nearly 20 million people.

Experts say that a planned residential project will affect the river's flow and have a negative impact on its ecology.

The request was made at a workshop organised on Tuesday afternoon by the Viet Nam Union of Science and Technology Association, the National Institute for Legislative Studies and the Viet Nam River Network.

The project, implemented by the Toan Thinh Phat Investment Architecture and Construction Joint Stock Company, was suspended in late March after receiving a huge wave of criticism from concerned scientists and experts after the company started to fill part of the river with rocks and sand last September.

Vu Ngoc Long, president of the Southern Institute of Ecology and a leader of a group that conducted research on the project, said that the company had poured a huge amount of rocks and sand into the river.

Long said the group had made shocking findings during their assessment of the project's environmental impact.

The report was compiled by the Institute for Environment and Resources based in HCM City in April 2014, he said.

Some of the report drew experience, including recommendations and solutions, from another report regarding a project to build the Vinh Hang Cemetery, also written by the institute in 2011, he said.

"It's unbelievable," he said.

The environmental impact assessment report for the housing project was carelessly compiled, but it still got the green light from local authorities, he said.

Dinh Xuan Thao, director of the National Assembly's Institute of Legislative Studies, said that the project violated a range of laws.

Building a housing development beside the river violated the Law on Water Resources. Scientists said the project would change the river's water flow, so it violated the Law on Domestic Waterway Traffic, he said.

Cancelling the project after a lot of money had been spent was a waste, but if would harm people and the environment, it should be stopped, he said.

Thao said scientists and experts had been asked to work together to find the best solution for the case.

Dr To Van Truong from the Ministry of Science and Technology also applauded the call to cancel the project.

"Humans can not always impose their own will on a river," he said.

Poor management

Do Hong Phan, an environmental expert, said that central-level management agencies did not know about the project until its construction started a couple of months ago.

However, Phan also questioned the effectiveness of central-level management agencies.

"How can they not know about the project when preparations started six years ago," he said.

In 2008, the provincial People's Committee gave approval to the Southern Institute of Water Resources Research to assess the impact on the river.

The project was given the green light in July 2014, with an estimated budget of VND2.2 trillion (US$101 million).