Scientists have warned of risks at reservoirs and dams

Since 2010, several incidents in dam execution and operation have occurred in Vietnam. 

Vietnam has many rivers and streams stretching from the northern hills and mountains, along the Truong Son Mountains to the central highlands and the east of the southern region. 

The main characteristic of the river system is that most of the main streams have short or medium length, with steep slope of the current and narrow basins. This facilitates the construction of hydropower projects at different water levels, but the damages will be serious if natural calamities occur, according to Le Anh Tuan from the Can Tho University.

There are over 6,500 reservoirs and dams, which serve electricity generation, flood prevention and watering. They also have other subordinate functions, such as supplying water, preventing salt water and serving waterways transport.

The biggest hydropower reservoir is Hoa Binh, built in 1979, with the capacity of 9.4 billion cubic meters of water, while the biggest irrigation reservoir is Dau Tieng, built in 1981, with the capacity of 1.5 billion cubic meters.

Most large reservoirs were designed and built 20-30 years ago on the basis of hydrological data of 1960s-1970s.

At the time of design, the water and flood situation was different from now, as designers did not consider possible changes due to climate change. Therefore, scientists have urged to ensure the safe operation of reservoirs and lakes in the peak storm season.

Tuan, in his article published on Thoi Bao Kinh Te Saigon, pointed out that ensuring the safety of small- and medium-scale hydropower dams has not received enough attention.

In general, large hydropower works are operated and supervised by many technicians, while there are early warning systems. 

By contrast, at small hydropower works, mostly located in remote areas with poor transport infrastructure conditions, there are not enough experienced workers and information is lacking. The works of this kind are at high risk.

Many accidents occurred at Song Tranh 2 (Quang Nam province) in 2012, at Dak Mek 3 (Kon Tum) in 2012 and La Krel 2 (Gia Lai) in 2011.

According to Tuan, no expert dares to affirm that the control systems will ensure safety for dams at present and in the future. Being on the alert, thus, is important.

The scientist emphasized the need for assessment and predictions about the risks for upcoming years. Local authorities need to build dam collapse scenarios to help them decide when and how to take action promptly in case of emergency.

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Mai Lam