Yangyel Lhaden

The recently constructed borewell—groundwater extraction—near the confluence of the Wangchhu and Hongtsho stream will help resolve the seasonal water shortage faced by residents of Babesa in Thimphu.

The borewell was constructed at a cost of Nu. 9.285 million.

The water shortage in Babesa worsens during the lean season, when the two water sources at Chamgang and Royal Thimphu College, dry up.

“Water sources in Motithang, Chamgang, and Ngabi Rongchhu above Royal Thimphu College have been experiencing a decline in the safe yield flow over the years,” a Thimphu Thromde official said.

In this wake, Thimphu Thromde is exploring alternative water sources, such as borewells, to ensure water supply during the lean season.

The new borewell is connected to the reservoir tank that distributes water to Babesa area.

“This site is ideal for a borewell due to easy accessibility for machinery, and its location at the lowest point near the convergence of the river and the stream aids in the natural replenishment of groundwater,” the thromde official said.

The thromde official also said that the borewell is constructed at a considerable distance from the Wangchhu, ensuring its safety from minor regular floods. 

The groundwater has been treated and meets the standards set by the Bhutan Water Quality Standard 2016. The assessment of water quality encompasses key parameters such as pH value, turbidity, hardness, conductivity, and total coliform levels, all of which are within permissible limits.

Thimphu Thromde is planning to construct another borewell on the left side of Babesa, which would benefit the entire Babesa area.

Thimphu Thromde has constructed three borewells near the flyover bridge that supplies water to Changbangdu and Changzamtok. A new borewell will also be constructed at the base of Debsi.

These borewells will provide a reliable water supply during the dry season.

The thromde official said that several studies indicate groundwater recharge as a potential water source to complement existing water sources.

According to the National Centre for Hydrology and Meteorology, Thimphu has received an average annual rainfall of 564.64 mm over the past 13 years. The Hydrology Report 2022 indicates that, on average, approximately 58 percent of annual precipitation contributes to groundwater recharge, with increases in both annual and summer precipitation expected to enhance this recharge. Snowfall in Thimphu and nearby mountains also contributes to groundwater recharge.

“The borewells will only be used in lean season ensuring that the groundwater is recharged during summer,” the thromde official said.  “In the dry season, groundwater will serve as a contingency backup when other water sources are insufficient, ensuring long-term sustainability.”

Extracting water with borewells involves using an electric pump, but this will not impact the current water tariff. “However, the government will review the operational and maintenance costs over time and adjust the water tariff rates as needed,” said the thromde official.

Thimphu Thromde will monitor the borewell’s water quality daily in line with the Drinking Water Quality Standard 2016, with oversight provided by the Royal Centre for Disease Control.