Too many wells give HCM City sinking feeling

Nguyen Huu Canh Street in Binh Thanh District suffers from heavy flooding due to tidal surges. Bigger tides, along with land sinkages blamed on the falling water table, are expected to cause more severe flooding in the city. —VNA/VNS Photo Hoang Hai

HCM CITY — HCMC is considering plans to improve the management of private artesian water bores as overexploitation of underground water sources is causing land to sink in many of the city's districts.

The land sinkage has been blamed on falling artesian water levels and land that is too unstable for the current rate of development.

"The overexploitation of underground water has been a large cause of land sinkage," Le Van Trung, director of the Geomatics Centre of the National University- HCM City, said.

Land in parts of districts 1, 4, 7, 8, 9, Binh Thanh, Thu Duc, Binh Chanh and Hoc Mon has sunk 10-15mm a year. The sinkage levels are expected to get much worse in District 9, Binh Chanh, Thu Duc, Hoc Mon and Binh Thanh districts by 2020.

Trung told a meeting of the HCM City People's Committee earlier this week that there were three main causes for the problem – unstable land, the construction of projects on unstable land, and the decline of underground water levels.

The combination of higher rainfall levels, bigger tides and land sinkage was a recipe for more severe flooding in future, Trung said.

The flooding of 79 out of the 116 roads had been exascerbated by lowering land levels, he said.

Deputy chairman of the HCM City People's Committee Nguyen Thanh Tai said the management of artesian water sources in the city was too lax and needed tightening.

Tai ordered the Department of Natural Resources and Environment to do an area-by-area assessment of the use of artesian water and organise a seminar on the impacts of water bores on land stability.

The People's Committee would use the data to map out areas where water bores and construction would be restricted.

The city would also increase inspections of artesian water bores and penalise anyone illegally exploiting underground water resources, Tai said.

The department has set a cap of 832,000cu.m a day of pumped bore water. Records show that 582,000cu.m a day was pumped in 2008.

Nguyen Ngoc Hong, deputy director of the department, said the real volume of underground water that was being pumped could be a third as much again.

In several industrial parks which have tap water, many companies illegally exploit underground water for production, especially companies that use a lot of water like leather tanners and textile and dye companies, according to the HCM City Export Processing and Industrial Zones Authority. — VNS

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Subterranean plan to boost city space

HCM CITY — The HCM City Department of Planning and Architecture (DPA) is set to study master planning for the use of underground space in the city to increase the effectiveness of urban land use, according to its chief.

The department's director, Nguyen Dinh Hung, said the main objective was to use space more efficiently while still ensuring that the city underground technical infrastructural system would develop stably and in tune with natutral conditions and meet the city's socio-economic development needs, Hung said.

The DPA will co-operate with other agencies to collect and update planning design and information related to existing technical infrastructure, he said

"Luckily, most industries that undertake urban technical infrastructure work have their own planning designs," Sai Gon Giai Phong (Liberated Sai Gon) newspaper quoted him as saying.

He pointed to the sewage and water supply services as an example: The drainage agency had a water drainage master plan ratified by the Government in 2002 while the water supply agency has submitted a plan for the next two decades for approval, he said.

The power utility has also drafted a master plan, as have the post and telecom agencies.

Though many of their plans are broad and lack details, they provide the planning department the basic information required for underground-space master plan, he said.

"Because HCMC has a complex geological structure, the People's Committee has ordered the Department of Science and Technology and other agencies to make geological and hydrographical maps.

"These maps will be very important documents based on which we can come up with proposals to ensure underground space is used effectively."

Like many other cities around the world, the city's underground space will be used to develop urban services like transport, technical infrastructure systems, public space, shopping malls, and amusement areas.

However, priority will be given to technical infrastructure, underground networks, tunnels, and parking sites.

The department will also study the location of buildings to create underground transport systems to complement surface systems.

But Hung admitted that making an underground master plan was a difficult job since the city's infrastructure was completed in many phases starting many decades ago during the French colonial times onwards.

The wars destroyed some of the infrastructure and documents relating to them, he explained.

To carry out proper planning, great support will be needed from industries and the Science and Technology Department with its geological and hydrographical maps, he said.

The lack of technical capability and funds were other major hurdles for the department to overcome, he said. —VNS

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Hanoi sinking, experts warn

Experts, backed by recent studies, are warning that unplanned underground water exploitation and improper zoning plans are causing Hanoi to sink, local news website Dat Viet reported Thursday.

A recent study by the Hanoi Institute of Construction Science, Technology and Economics under the city’s Department of Construction, showed that Hanoi is subsiding every year, by 22.16 mm in Phap Van urban area to 41.42 mm in Thanh Cong Ward, according to the news source.

It also quoted another study by the Association of Hydrogeology and Construction Geology as saying that the Linh Dam and Thanh Cong areas are at very high risk of subsiding because of excessive construction and underground water projects.

Weak soil, in fact, is distributed across Hanoi, putting some places at risks of sinking, Do Minh Toan, former dean of Hanoi University of Mining and Geology’s Geology Department, told the news website.

The deeper underground water projects are conducted, the higher the risk of collapsing constructions, he warned.

He said new urban areas with many multi-story buildings have been planned in areas with very high sinkage risks like Ngoc Khanh, Giang Vo and My Dinh.

The subsidence also affects the accuracy of figures on the  maximum possible height of a construction project, he stressed.

Agreeing with Toan, engineer Le Tu Hai said weak soil was causing easily recognizable impacts like cracks and subsidence at constructions with weak foundations.

On the other hand, it implies effects that can't be realized in a short time like the risks of distortion and collapse of constructions, the engineer told Dat Viet without saying how many years of life the constructions can have.

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City grapples with zoning plan

Work starts at the Le Van Tam Park underground parking lot in HCM City. The parking lot will accommodate more than 1,900 vehichles and cost US$110 million to build. — VNA/VNS Photo Hoang Hai

HCM CITY — A plan to zone underground space in HCM City has been proceeding at snail's pace, creating major hurdles for several infrastructure construction projects like sewage and drainage systems.

The Government issued Decree 41 on urban development three years ago, mentioning the need for planning underground spaces, especially in the big cities like Ha Noi and HCM City.

This April, it issued Decree No 39 on underground space management, but besides a team was set up specifically for this purpose, nothing of note has happened.

Hoang Minh Tri, head of the HCM City Planning and Construction Institute, said current underground infrastructure was too complicated to make zoning plans. It would be a very expensive proposition to investigate current underground structures for zoning purposes, he added.

Records of past underground constructions or even recently built projects are insufficient to act on, and this lack of information has been blamed for the tardiness of several major projects.

Contractors had to work hard to investigate already existing underground works before they began implementing their own constructions. The time consuming work has badly delayed projects and even led to some cancellations, costing both the city and the contractors a lot of money.

The contractors have also said that the erection of "green fences" on city streets for a long time is also due to many "unexpected" underground structures.

Vuong Hoang Thanh, deputy director of the East-West Highway project's management board, said before starting the project, contractors had researched current underground constructions that would need to be relocated.

But it has happened several times that when workers ran into electricity supplying wires or a network of telecom cables, the contractors were unable to find their owners and negotiate their removal.

There have also been instances where companies have been unaware of their own underground works. It is only when contractors removed them after failing to get a response to media advertisements about such works that the companies have become aware, because of problems with their sewage, drainage or electricity cable lines.

The East-West Highway project is not the only one facing the underground mess. Other contractors working on similar projects have also had the same problem.

Tri said this was a consequence of history, with many underground constructions built by the French administration, the Sai Gon regime, and by the Government after 1975.

Materials about the structures were mislaid during the long years of war and this made it difficult to update information and initiate underground space planning, he said.

The underground conundrum has affected major infrastructure projects like the subway as well as underground parking lots.

Recently, the city began work on the subway and an underground parking lot under Le Van Tam Park.

However, even before two of the city's seven metro lines and the Le Van Tam Park underground parking lot broke ground, several buildings had begun construction with underground structures that could come in the way of these major projects. — VNS

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HCM City digs deep to resolve land shortage

Customers shop at Vincom Centre Shopping Mall in District 1, HCM City. The centre, which has seven underground floors, is the city's first project of its type. — VNA/VNS Photo Phuong Vy

HCM CITY — Many infrastructure projects in HCM City are making use of underground spaces as above-ground space dwindles with the city rapidly developing.

The first project of this kind was the underground facility under Chi Lang Park in District 1 under the Vincom Centre commercial/residential complex.

The centre, which was completed in April, has seven underground floors with a total area of 80,000 square metres.

At 20-metres deep, it has four upper floors for commercial services, restaurants and other services while three underground floors are used as parking lots.

Another underground project at Eden Quadrangle in District 1 will have four underground floors while a high-rise building with five underground floors will be built on the current site of Sai Gon Tax Trade Centre. These underground constructions will be eventually connected to each other and to the subway system's centre station in Quach Thi Trang Square by subway lines along Dong Khoi, Nguyen Hue and Le Loi streets.

Early this month, the construction of an underground parking lot began in Le Van Tam Park in District 3.

The city's first underground parking lot has 103,000 square metres, including five floors capable of accomodating 3,300 vehicles of all kinds and three levels for commercial services.

Another underground construction at Trong Dong Stage, District 1, is scheduled to be built by the end of this year.

The VND888 billion (US$46.5 million) construction built on 5,300 square metres includes a multi-level parking lot, commercial services and a stage.

There are also underground building projects that will be carried out at Hoa Lu Stadium and at a football pitch at Tao Dan Park.

In addition, most new or in-the-pipeline high-rise projects have or will have underground spaces.

Many experts said that building underground works was a current trend. According to architect Nguyen Truong Luu, when surface transportation cannot meet demand, building underground is inevitable.

But for effective and appropriate use of underground space, a comprehensive, detailed plan was needed, he said.

The underground spaces need to be connected to each other like an underground city, and a sensible arrangement of transport will reduce congestion in downtown city.

HCM City has no underground-space planning yet. Allowing investors to build separate facilities could create obstacles in later planning, Luu said.

He said that planning the underground network was necessary before further work is carried out. — VNS

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Cables to be buried in 15 streets in HCM City

HCM CITY — A new system of underground cable network will be installed in HCM City's districts 1, 3 and Tan Binh to replace the powerlines and telecom cables interlacing the city streets.

Fifteen streets in districts 1, 3 and Tan Binh are expected to be clear of powerlines and telecom cables, an eyesore of the city for years.

Tran Van Thanh, deputy director of the city Telecommunication Control Agency said the underground work would be completed at the end of this year.

Concerted efforts by relevant authorities including telecommunication, road construction, electricity and urban hygiene will be made to ensure the project schedule, according to the official.

No newly-built pavement will be excavated for the cable underground work.

Non-profit university gets first building

LONG AN — The non-profit Tan Tao University, situated inside the Tan Duc Industrial Park in southern Long An Province has inaugurated its first building.

It is the first of 64 buildings planned to be built in the next 15 years in the 103-ha campus at a cost of around US$400 million, said Dang Thi Hoang Yen, chairwoman of the HCM City Stock Exchange-listed Tan Tao Investment and Industry Corp , which owns the university.

Yen also announced full scholarships for all 500 students to be admitted to the 2010-14 course.

Ascott Ltd organises Blood Donation Day

HCM CITY — The Ascott Limited, a serviced residence operator in Viet Nam has joined with the Viet Nam Red Cross Society to organise a humanitarian blood donation on August 20 and 27.

Some 200 Ascott staff and residents staying in the 5 Somerset serviced residences in Ha Noi and HCM City would join in the event. The programme aims to help improve the public awareness of voluntary blood donation. — VNS

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