VietNamNet Bridge – The Dong Nai River has been playing a very important role
in the development of the HCM City as the southern economic center. Therefore,
when the river gets polluted, the economic center has suffered.
The dead sections of the river
A report showed that there are 39 underground water wells managed by the Saigon
Water Supply Company. Of these, 11 wells were built after 1975, while the other
old wells have been repaired and exploited to provide water to the city.
There are also other underground wells funded by UNICEF, namely the Hoc Mon
Water Plant with the capacity of 50,000 cubic meters a day that provides clean
water to districts 6, 11 and Binh Tan, and the Binh Tri Dong water supply
station, 12,000 cubic meters a day. HCM City’s dwellers have also been using
water from some 100,000 wells built by themselves.
However, the underground water quality has been degrading seriously due to the
serious pollution of the rivers and canals. Therefore, HCM City has been relying
on some key water supply plants.
These include the Thu Duc water plant which has the capacity of 750,000 cubic
meters per day, the Binh An BOT water plant 100,000 cubic meters and the Tan
Hiep 300,000 cubic meters. All the three plants use the water from the Dong Nai
River.
However, the Dong Nai River, the main water supply source for the water plants,
has also become seriously polluted. The Ministry of Natural Resources and the
Environment reported that the river’s water quality is getting worse with many
sections of the river getting “dead” because of the overly high pollution.
The water of the Saigon River, which begins from the Thi Tinh river mouth, has
been found as having pollution in organics and microorganisms. In the river
section that runs across HCM City, the BOD5, COD and microorganism indexes all
cannot meet the standards to serve as the clean water for domestic use.
The indexes about the water quality provided by monitoring stations showed the
degradation in the quality. The downstream of the Dong Nai River has also been
facing the salinity intrusion.
In November 2012, the salinity level measured on the Thi Vai River hovered
around 10.2 and 24.9 ‰, or 2‰ higher than that in September 2012.
The salinity level has been increasing rapidly since 2009. In that year, the
salinity was measured at 1,700mg per liter, while it rose to 3,400 mg per liter
in the dry season of 2011. As a result, water supply plants have to pay more
money on necessary chemicals to process the raw water, thus leading to the
higher water production costs.
Meanwhile, healthcare experts pointed out that the increase in the volumes of
chemicals used can only settle some major problems, while the current ways of
treatment still does not allow eliminating some kinds of heavy metals.
Environmentalists have warned that with the current speedy sea water rise and
the operation of a series of hydropower plants on the Dong Nai River, the
salinity intrusion would be even more serious, which may reach out to the Hoa An
raw water pumping station.
Water reservoirs raise worries
A series of irrigation and hydropower plants have been and would be built on the
upstream of the Dong Nai River, which has been considered the big threat to the
city.
It is expected that 14 hydropower plants would be set up on the main stream of
the Dong Nai River. All of them are big and medium scaled, of which six have
been operational.
Experts have warned that the water reservoirs of the hydropower plants would be
the “bombs” to be dropped into the city.
NLD