Buildings in Yangon may be threatened as high-rise developments draw an unprecedented volume of water from beneath the city, prompting authorities to consider alternative ways to meet increased demand.
Yangon City Development Committee can supply around 135 million gallons of water to the city daily.
However, Yangon residents consume almost double this – over 200 million gallons – said U Khin Maung Tint, chair of the Committee for Quality Control of High-Rise Building Projects (CQHP), in an exclusive interview with The Myanmar Times.
The committee is under the Ministry of Construction, and supervises high-rise design and construction.
Many rely on water from lakes and rivers, or on tube wells, which are often unlicenced but are more convenient than the YCDC distribution system, said U Khin Maung Tint.
Local authorities do not have the capacity to supply running water to new high-rise projects, which instead must rely on building their own tube-wells. These are far larger than the small individual tube-wells, and will require much more water.
There is no comprehensive research on the long-term impact of this, said U Khin Maun Tint. He fears that land may gradually sink, affecting the stability and strength of buildings.
“The daily consumption of underground water is 30 million gallons at least. The higher the consumption, the greater the impact on the stability of buildings across the city,” he said.
Land near to Kyeemyndaing and Ahlone townships is most at risk, as it is built on silty soil. Land around Thein Gyi Market and the Shwedagon Pagoda is a mixture of sandy and laterite soil, said U Khin Maung Tint.
The best soil for building is around Kamaryut and Hledan in north-western Yangon, as it is compact. The soil in Tarmwe, Mingalar Taung Nyunt and Pazundaung townships is also fairly good, he added.
Foundations can be reinforced to make the bottom of a building stronger, but there is nevertheless a risk that the land under the building could sink if the use of underground water rises.
The issue could be solved if YCDC found another way to supply water, rather than allowing high-rise developers and other residents to draw it from underground, he said, adding that extensive research is necessary.
YCDC is aware of the issue and is building a new reservoir to increase its water supply capacity. Once this is complete, YCDC will be able to supply 40 million more gallons of water to residents daily, said Yangon Mayor U Hla Myint to parliament in June.
The CQHP believes use of underground water is on the rise, but there are no exact figures. Until accurate data is collected, it will be hard to discover where soil is less stable, experts said.
There is no official government body tasked with collecting data on underground water use, or planning for the future. Myanmar’s groundwater resources were once protected by the Burma Underground Water Act of 1930, but the law is not applied properly these days, said experts.
Extracting underground water carries other risks beyond ground sinking, said the CQHP’s vice chair U Salai Myo Myint. “If we extract too much water from beneath the city, salt water may enter, leading to difficulties securing pure water,” he said.
Geologist U Soe Thura Tun previously told The Myanmar Times that excessive use of groundwater can lead to water resource depletion, ground subsidence and saltwater intrusion.
“Twenty years ago artesian wells were dug in Yinmarpin township in Sagaing Region. Around 10 years later the wells were inundated with saltwater,” he said.
“This occurred because the surface water was depleted, and the saltwater stored in the rocks at a deeper level was pushed upward. This kind of effect can occur in Yangon because it is surrounded by seawater.”
Water from tube wells can also be detrimental to health, if it is not properly regulated, said experts.
Rain can be stored underground, but the volume of absorbed rain has fallen, as concrete is laid over much of the city, said U Khin Maung Maung, central executive at the Myanmar Engineering Association.
“Instead, substantial amounts of rain-water drain into the rivers, raising the risk of flooding. Some of the rain seeps into the ground, but we don’t know if this filters through to the main supply of underground water.”
In Mandalay, local authorities considered working with international partners to compile data on underground water use, but the cost of the project turned out to be too high.
Source: Myanmar Times