VietNamNet Bridge – The encroachment of sea water into the Dong Nai-Saigon river system has soared, affecting the supply of freshwater for agriculture and daily life of millions of people in HCM City.

Nguyen Minh Giam, deputy director of the Southern Region Hydrometeorological Station, said that “the latest data collected at some rivers in the south shows that this year’s salty water encroachment occurred more early, and at higher level than previous years.”

Many rivers in the southern region are infected with salty water at very high levels, which are several times over the threshold. For example, the Nha Be River with 15 g/liter; Vam Co Dong River 4.6 g/liter; and the Vam Co Tay River 3.3 g/liter. The Vietnamese standard for salt in fresh water for daily life is under 0.25 g/liter.

Salty water has encroached deeply into canals inside HCM City. For instance, Doi, Te canals 3-4 g/liter, with An Ha and Xang canals at 1-2 g/liter.

The Saigon Water Supply Corporation said that “the encroachment of salt water has affected its operation.” To reduce the saltiness, Dau Tieng reservoir has to discharge water for the fourth time.

Bui Xuan Dai, Deputy Director of the Dau Tieng Irrigation Company, said “that on March 16, Dau Tieng reservoir discharged over 3.8 million cubic meters of water to reduce the saltiness in the downstream of the Saigon River, to save Tan Hiep Water Supply Factory (300,000 cu.m/day in capacity).”

The Dau Tieng reservoir’s water level was 19.58m in the morning of March 17, only 2.58m over the dead level. The reservoir is getting dry due to drought, but it still has to discharge water to push back sea water and to supply water for Tay Ninh and HCM City.

Hydrometeorological experts said that “this year’s sea water comes early and encroaches more deeply into southern rivers because the water volume in the upstream is very modest. Moreover, upstream hydro-power plants have stored up more water to produce more electricity for the dry season, resulting in more serious salt water encroachment in the downstream.

March and April is the peak of the dry season. The saltiness in southern rivers is forecast to increase.

PV