Elisabeth Oktofani & Dofa Fasila – A city official has admitted that there would be no end to the dredging of Jakarta's rivers as long as people keep dumping waste in them.

Suprapto, head of rivers and coastal areas at the Jakarta Public Works Office, said on Tuesday that no amount of clean-up efforts would suffice as long as residents continued to choke the city's waterways with trash. "Every day the Public Works Office dredges up to 27,000 cubic meters of plastic trash from Jakarta's rivers," he said.

"We might have the necessary equipment to keep doing it, but every day there's just more and more plastic waste in the water. So it's really up to the citizens to dispose of their domestic waste properly, whether plastic or liquid, because the city is already doing all its can to clean up the rivers."

He added that besides degrading water quality, the trash also hampered the flow of the rivers, making them flood more easily during heavy rains.

"The damage to river basin areas and the subsequent flooding are basically due to the constriction of the water flow because of the amount of waste being dumped," he said.

"Take the Pesanggrahan River [in South Jakarta], for instance. The water quality there is exceptionally bad. Since 2008, we've had to dredge it three times just to restore normal water flow."

Rusman Sagala, head of conservation and environmental management at the Jakarta Environmental Management Agency (BPLHD), said the Pesanggrahan was heavily polluted with both biological and chemical contaminants.

"According to our data, 82 percent of the pollution in the river comes from domestic waste, either the liquid or plastic," he said. "That's because all the waste is going directly into the river untreated."

He added it was important for citizens to break the habit of dumping waste into waterways.

"We can't keep our eyes on all Jakarta residents, 24 hours a day, fining them for throwing waste into the rivers," he said. "That's impossible, so that's why we need urge citizen involvement to address this issue."

Separately, Jakarta officials welcomed an offer by private water operator Aetra to revise its contract with the city, which officials previously complained would have left the city with mounting debts.

"I appreciate Aetra's offer to revise the contract that thus far has tended to be to the city's disadvantage," Governor Fauzi Bowosaid. "I hope the city's other water operator now follows suit," he added, referring to PAM Lyonnaise Jaya (Palyja).

Under the current contract, the city subsidizes Aetra for providing piped water to residents. That leaves it unable to raise prices for consumers until a minimum standard of service has been attainted.

The proposed revision would tie the payment of subsidies to the operator's performance in providing a reliable water supply and bringing in new customers.

Mohamad Selim, Aetra's president director, said revising the contract would not be to the company's detriment.

"I'm optimistic that Aetra won't lose out, even taking into account inflation and rising costs of production," he said. "We've calculated the risks and found that we will still stand to profit."