Commercial buildings ‘likely rely on groundwater’

Despite claims by many building managements in the city that they rely entirely on tap water for their daily operations, experts say it is more likely many have drilled illegal wells to tap groundwater, contributing to land subsidence.

The management of Senayan City Mall and PT Unilever Indonesia have said they rely entirely on tap water for their buildings’ operations.

“Depleting groundwater in the city has been a concern for us since this mall’s establishment in 2006. For our daily operations we completely depend on tap water,” Senayan City public relations and tenant communications manager Sri Ayu Ningsih told the The Jakarta Post.

Unilever’s head of corporate communication Maria Dewantini Dwianto said, “Our building on Jl. Gatot Subroto in South Jakarta relies entirely on tap water and we never have supply problems.”

Firdaus Ali, a board member of the Jakarta Water Supply Regulatory Body, said it would be difficult for a commercial building to rely entirely on tap water.

“Thirteen rivers passing through Jakarta are heavily polluted... and could not supply enough clean water for the growing population and development in the city,” he told the Post on Wednesday.

Jakarta’s tap water supply is 4,000 liters per second, which is less than the demand in 2010 based on an assumed population growth of 0.3 percent per year. The Jakarta Statistics Agency recently announced that the population of the city was growing on average at a rate of 1.3 percent per year.

Firdaus said that almost all commercial buildings used groundwater not only because they lacked required resources for the city supply but because the city’s tap water piping system was inadequate.

“Our preliminary finding shows that these companies use water from illegal wells... they have eight wells but report to the Jakarta Environment Management Agency [BPLHD] that they only have two,” he said.

Although the BPLHD reported that the annual use of groundwater in the city for commercial buildings was 22 million cubic meters, many experts believe it is closer to 200 million to 300 million cubic meters.

They said the maximum safe level of groundwater usage in the city was between 30 million and 60 million cubic meters per year.

“A recent study even found that the safety level might be lower as it found that our groundwater came only from Depok, contrary to previous assumptions that Bogor also supplied the city’s groundwater,” he said.

Experts from the Bandung Institute of Technology have said the exploration of groundwater and the pressure from the weight of high-rise buildings were the main contributors to land subsidence in Jakarta, which was occurring at a rate of 10 centimeters per year.

A 2007 bylaw stipulates that groundwater users in commercial and industrial buildings must pay taxes that would be more costly that paying for tap water.

Last year, the BPLHD sealed 162 commercial buildings that had built illegal wells to extract groundwater.

BPLHD head of law enforcement Ridwan Pandjaitan said, “This October, we will be working together with tap water operators to check 500 industrial buildings in Pulo Gadung in East Jakarta. We will encourage them to use tap water and will take legal action if they refuse to use tap water.” (rch)