Hanoi plans to build surface water plant
VietNamNet Bridge – Hanoi authorities gathered a meeting some days ago to discuss the surface water exploitation--amid the warning that the underground water cannot satisfy the increasing demand of the city.
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Dr Nguyen Van Tuc, Director of the Institute for Water Technology and the Environment, has affirmed that Hanoi is lying on a huge underground water tank covering thousands of square kilometers. He has denied the opinion of a consultancy firm that the underground water reserves of Hanoi are just about 700,000 cubic meters per day, and that the reserves have been fully exploited.
Tuc has affirmed that the reserves of the underground water in Hanoi are about 8.3 million cubic meters per day, not 700,000 cubic meters. The water wells have the capacity of 3000-4000 or 5000-6000 cubic meters per day. At every well, the main underground water layer for exploitation is just in the depth of 50-80 meters, while the most popular depth is 60-70 meter.
The Hanoi Department of Natural Resources and the Environment, in its report, showed that the underground water reserves for exploitation are about 8,362,000 cubic meters per day, while the gravel aquifer alone can provide 5,850,000 cubic meters per day, accounting for 70 percent of the total potential underground water reserves of the whole city.
Currently, the city just exploits 981,000 cubic meters per day, less than 20 percent of the total potential underground water reserves of the gravel aquifer and just 12 percent of the total potential underground water reserves of the whole city.
Also according to Tuc, the result of the water level monitoring work showed that only the underground water level of the wells far from the Red River, such as Ha Dinh and Mai Dich, has been lowered, while the wells located near the river, including Thuong Cat, Nam Du, Luong Yen, Cao Dinh and Nam Du still have been working normally. The water level of the wells have not been lowered too sharply because they always receive the water supply from the river.
Tuc, while affirming that the underground water is enough to satisfy Hanoians’ demand, said that Hanoi should not build a surface water plant. On the southern river bank, it would be better to use up the capacity of the Song Da Water Plant, designed to have the capacity of 300,000 cubic meters per day. Meanwhile, on the northern river bank, the technical conditions are not good enough to build a water plant, both in the technical conditions (the quality of water resources) and investment efficiency.
The Bac Thang Long water plant on the northern river bank has the capacity of 50,000 cubic meters per day, while only 37,000 cubic meters have been used, while the figure is 34,000 cubic meters in Gia Lam and Long Bien districts.
In order to exploit the surface water of the Duong River, it would be necessary to build a big plant with the capacity of 100,000-150,000 cubic meters per day. When will Hanoi use up the designed capacity and will it be able to take back the investment capital. Meanwhile, it would be better to use underground water than build small capacity water plants (30,000-60,000 cubic meters per day).
Tuc has also expressed his worry about the quality of the surface water. Since early 2011, the Red River’s water in Lao Cai City was found as seriously polluted from the upper course. The Hanoi Department for Natural Resources and the Environment’s report shows that some stretches of Hong and Duong rivers which go through Hanoi have been seriously polluted.
Source: Lao dong
