HCM CITY — The Sài Gòn Water Corporation (Sawaco) has submitted a plan to build underground water tanks around HCM City to store water from treatment plants.

They will be built in major parks and at the sites of elevated water towers in all districts, starting with Gia Định Park in Tân Bình District, Sài Gòn Zoological and Botanical Garden District 1, Phú Lâm Park in District 6, Culture Park in Gò Vấp, Tân Phú District’s underground water supply plant, and Nguyễn Văn Linh street in District 7.

They have been envisaged following high salinity in the rivers during the dry season and pollution.

The Japan International Cooperation Agency (JICA) had suggested building a 35,000cu.m underground tank in Gia Đinh Park just before the national electricity grid tripped in May 2013 leaving 22 southern provinces without power and water pumping stations unable to work.

Sawaco said the plan is based on this suggestion.

In the dry season this year the 300,000cu.m Tân Hiệp Water Supply Plant and 100,000cu.m Bình An Water Supply Plant had to stop drawing water from the Sài Gòn and Đồng Nai respectively due to high salinity.

The two rivers are the major source of water for the city’s 10 million people.

“We have suggested how to build large underground water tanks ... and such constructions have been successfully done in Thailand and Japan,” Bùi Thanh Giang, deputy general director of Sawaco, told Tuổi Trẻ (Youth) newspaper.

The city’s water supply plants are located along the Sài Gòn and Đồng Nai in Thủ Đức and Củ Chi districts, dozens of kilometres apart. Thus, water pressure and the chlorine content are not uniform, being higher near the pumping stations and lower elsewhere, he said.  

Setting up pumps at the tanks, which would be linked with the existing water pipe network, would mean distributing the pressure and chemical more evenly along the network.

However, the plan is still at an early stage and installing the underground water tanks is not part of the HCM City water supply master plan approved by the Government.

Thus, city authorities need to make changes to the master plan and get fresh approval, he said.

Prof Dr Lê Huy Bá of the HCM City Industry University’s Environment Institute said he approved of the plan if it was for preventing flooding by storing rainwater.

“But building the system to store treated water is a different issue and needs more studies to ensure the quality of water and cost.”

Võ Kim Cương, a former deputy chief architect of the city, pointed out that HCM City is sinking and wondered what effect storing a huge amount of water under the ground would have on it. — VNS