'Dewatering' shares blame for city's water woes

The Jakarta Post, Jakarta

The unchecked construction of malls and high-rise apartment buildings could add to water shortages in the capital, an official said Wednesday during an impromptu visit to an apartment building in South Jakarta.

During construction, developers often use a process called dewatering to drain water from the ground, which may affect wells dug in residential areas, said Peni Susanti, head of the Jakarta Mining Agency.

Some of the extracted water is also not properly redirected, being sent toward sewers instead of being stored or utilized, she said.

"The city water supply is scarce, developers should not just be throwing it away," Peni said while inspecting Gandaria City, a mall and apartment building currently being constructed on Jl. Iskandar Muda.

During the inspection, officials from the mining agency found one spot where clean water was being redirected to sewers outside of the walled construction area.

"This will not do, it is a waste of clean water and you need to at least redirect the plumbing into an aquifer or a water storage facility," Peni told developers.

Construction workers are digging a basement for Gandaria City, which requires the groundwater to be extracted and redirected.

Peni said any water extracted during the dewatering process should be stored and reused later.

After the site was inspected last year, 10 pipes were installed to recharge water back into the ground, according to Indramawan, a representative for the developer of Gandaria City.

Dewatering could also affect the surrounding community as the process drains groundwater with a certain radius, usually 40 to 50 meters depending on the technology,

Imam Sudjono, head of groundwater control subdivision at the mining agency, said Wednesday's inspection was done in response to complaints from residents who were having trouble finding groundwater.

"I've received complaints from people saying they can't find water even after drilling wells as deep as 15 meters," he said.

Gandaria was not the only high-rise development reprimanded for wasting extracted groundwater during construction.

Earlier Wednesday, officials from the mining agency visited an apartment building currently being constructed at Rasuna Epicentrum, South Jakarta. Imam told the developer to obtain a permit for using the drained water.

Imam said agency officials planned to inspect other high-rise developments in Sunter, Kelapa Gading and Mangga Dua in North Jakarta.

High-rise buildings are heavy users of groundwater, reducing groundwater elevation by up to two to five meters a year in the city, according to data provided by the agency. (anw)