VietNamNet Bridge – The ministry of Agriculture and Rural Development plans to upgrade nationwide weak dams at a cost of US$460 million to improve their safety, but is hampered by the fact that many of them do not have complete technical information, delegates heard at a recent seminar on "Improving management for reservoir safety".

Flood waters from the Tra Khuc River overflow the Thach Nham Irrigational Work in the central province of Quang Ngai. The country will check and upgrade weak dams to cope with flood waters.

"If we do not have enough data to know which the weakest reservoirs are, we cannot start the project," Deputy Minister of Agriculture and Rural Development Hoang Van Thang was quoted as saying by Sai Gon Giai Phong (Liberated Sai Gon) newspaper.

According to figures from the ministry, around 17 per cent, or 1,150, of the dams in the country are degraded and need upgrades to ensure safety.

Of the 6,648 reservoirs, 560 are large ones with a capacity of over of 3 million cubic metres while over 1,750 are small with capacities of 0.2 - 0.3 million cubic metres.

Most small and medium-sized reservoirs were built 30 - 40 years ago and cannot cope with the increasingly severe floods, experts fear.

"There are 151 reservoirs in the central province of Quang Binh but most of them were built before 1989 with funding from both the Government and local people," Dang Tien Dung, deputy director of the province Department of Agriculture and Rural Development, said.

Most of them were seriously degraded but the province had no money to fix them he said.

Doan Duc Thien, deputy head of Hoa Binh province's Irrigation Sub-department, said about his province: "All reservoirs in Hoa Binh were built over 55 years ago. Most of their technical figures are incomplete."

Phan Cong Ngon, head of the Irrigation Sub-department in the Central Highlands province of Lam Dong, said only 100 out total of 217 dams in the province could be certified as safe.

In the central province of Thua Thien Hue, dams are large, with capacities of 10-100 million cubic metres and all were built in the 1980s.

Tran Kim Thanh, deputy director of the province Department of Agriculture and Rural Development said: "Last year four earthquakes of magnitude four occurred in Hue and we have reviewed all reservoirs. The worry is that all reservoirs are designed for only magnitude 4.7 earthquakes. If a severe earthquake hits, the consequences will be terrible."

He urged relevant authorities to carefully study all reservoirs to ensure safety.

"All reservoirs are located in upstream areas and if they can't be safe, they will become a serious threat."

The Government spends a lot of money every year for upgrading dams but the results do not seem to show that.

Thang said: "Repairs are more expensive than building new ones. The limited application of technology in upgrade, management, and operation of dams is another reasons for the unsafe situation."

VNS