HCM City facing landslide and fresh water shortage

Published: 11/06/2011 05:00


The latest reports show that the underground water level in HCM City has fallen to – (minus) 46 meters, while the water reserves in the city have also been decreasing rapidly.

The latest reports show that the underground water level in HCM City has fallen to – (minus) 46 meters, while the water reserves in the city have also been decreasing rapidly.

Alarm bells have been rung by scientists

According to Dr Nguyen Viet Ky from the HCM City University of Technology, the figures showing the dramatic decreases of the water levels of all aquifers in HCM City show many high risks. The water volume being exploited is bigger than the reproduced water volume, or in other words, the natural water volume that aquifers receive every year is much smaller than the water volume exploited every year.

At the same time, the rapid decline of the water level has been accelerating the expansion of the salty areas, while many fresh water wells have become useless because of the high salinity.

The rapid water decline has also increased the risk of surface subsidence of the city – which is a popularly seen phenomenon in many places in the world.

HCM City is considered one of the ten places which bear the biggest influences of the global climate change (it will lose much land due to the sea water rise). Meanwhile, the surface subsidence due to the massive water exploitation will make the problem more serious.

According to the HCM City Environment Protection Sub-department, the water levels measured at all the observation stations all have decreased by 0.36-2.1 meters in comparison with 2009. This shows that underground water in HCM City has been exploited in a massive scale, especially in deep water layers.

Regarding the quality of underground water, the concentrations of heavy metals such as Cu, Pb, Zn, Cd, As, Cr measures at observation stations in 2010 increased by 1.1-12 times in comparison with 2009. It is clear that the water level decline has led to the penetration of polluted substances to water layers, thus making the water quality worse.

Dr Ky said that if the situation cannot be improved, and the water level decline continues, the water supply to the city will become limited, especially when the water from the Saigon and Dong Nai rivers have been threatened with the pollution from the industrial zones and residential quarters along the rivers’ banks

What to do?

According to Ky, the city’s authorities have realized the risk and taken actions to settle the problem. The city has defined no-water exploitation areas and the areas where water exploitation limitation is set. Especially, in un-prohibited areas, the water exploitation must not be made at the depth of over – (minus) 40 meters,

Another measure which has been used in HCM City is providing “artificial supply”, i.e bringing high quality surface water to the aquifers, especially in the areas, where the water levels decline sharply such as Tan Binh and Hoc Mon.

However, it seems that there is no high quality surface water (from river, canals, lakes and ponds) in HCM City any more. The only solution for now is collecting rainwater to bring to aquifers, which both allows easing the flood and helps increase the underground water reserves.

The HCM City University of Technology is now carrying out the project on collecting rainwater from roofs and brings to aquifers, which has shown good initial results.

Phan Chu Nam, MA, from the Federation of planning and investigation of water resources, also thinks that it is necessary to define the areas where underground water exploitation is prohibited.

The expert also believes that it is necessary to carry out a research on the hydrogeological conditions of the territory, which is very useful for the underground water resources management.

The areas where water exploitation is prohibited would include the districts in the inner city; from Tan Phu district (where there is the Hoc Mon Water Plant) to districts 10, 11, 5, 8 and 7. These are the areas with high construction density and latent risks.

Source: SGTT

Provide by Vietnam Travel

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