Adianto P. Simamora, Jakarta – Most small lakes in Greater Jakarta are getting shallower as local authorities are not prioritizing their protection, an official said last week.

Even worse, the water in some lakes is no longer fit to be used even for agricultural activities.

"About 60 percent of the roughly 200 lakes in Jakarta, Bogor, Depok, Tangerang and Bekasi were damaged in 2002. It might have now soared to 80 percent," Antung Deddy, assistant deputy for river and lake protection at the ministry told The Jakarta Post.

He said that several factors were damaging the lakes, which serve as catchment zones in the wet season and water reserves during the dry season.

"The heavy sedimentation make the lakes get shallower, thus degrading their ability to contain rainwater," he said. "The rising population of Greater Jakarta is the main cause (as it) converts the lakes into residential areas. Many residents often claim them their own property," he said.

He said that the residents also used the lakes as dumps for both domestic and industrial waste. "People remain unaware about the importance of the lakes. They can contain rainwater and prevent flooding," he said.

Antung said that the administrations of Jakarta, West Java and Banten signed a memorandum of understanding to restore the lakes in 2004. "But there has been no real action yet to implement the agreement," he said.

The agreement, outlining 21 actions to take place between 2004 and 2010, was signed by three governors, three regents and four mayors in Greater Jakarta.

Data from the ministry shows the average area of the lakes is six hectares, with a depth of about five meters. The largest lake is Garukgak in Tangerang, at 130 hectares. As of 2003, there were only 1.4 million ha of lakes in the region, a sharp decrease from the previous year's 2,3 million ha.

The Public Works Ministry has calculated that if the government could return the lakes' area to 2.3 millions ha, they could contain about 116.8 million cubic meters of rainwater. Thus, if the volume of rain falling in Jakarta reached 15,000 cubic meter per second, the capital would be free of flooding

Jakarta alone currently has 42 lakes, but five of them have been converted into business areas.

"Another 16 lakes with a total of 168.4 ha, Rawa Kendal and Rorotan lake in North Jakarta, Penggilingan Lake and Segaran and Dirgantara lakes in East Jakarta have been receding due to land conversion," the ministry said

In Bogor, 93 lakes with a total area of 500,130 ha have shrunk by 29 percent. "The local people converted the lakes for agricultural areas,"the ministry said.

Of the 93 lakes, locally known as situ, 15 are in poor condition, while two other have been transformed into part of the West Java turnpike, in Babakan Madang, and a school, in Gunung Putri.

Sukiswanto of the Bogor Road and Water Agency said that most of the remaining lakes were experiencing sedimentation, usually caused by poor maintenance.

Bogor's lakes, Jasinga, Lewiliang, Parung, Jonggol, Ciawi and Cibinong, range from one to 35 hectares in size.

Sukiswanto said it was hard to prevent lakes being converted into land. "To restore the lakes we will need a huge amount of money, but as some of the lakes are under the authority of the provincial government, we must wait for their initiative," he said.

The lakes in Depok are an indispensable source of groundwater to Jakarta and are now also in a poor state because residences have been built along them. "At least 23.4 hectares of the lakes have been affected due to severe sedimentation and illegal occupancy," he said.

The lakes of Tangerang are in the worst condition, however. The 38 lakes originally had a combined area of 1,065 ha – now they cover only 686.7 ha. The government has allocated Rp 250 billion to restore the lakes, either through leaning or dredging, as part of efforts to avert future floods in the capital.

"We are still mapping the lakes. The Public Works Ministry will lead the restoration job this year as part of the government's master plan to cope with floods in the coming years," he said.

The city administration said it had not received any orders from the government to restore Jakarta's lakes.

"It is a new program. We are not yet ready to restore the lakes because we don't have a budget allocated for them" said Daniel Abbas, who oversees environmental damage control at the Jakarta Environmental Management Agency.

Jakarta has repeatedly asked neighboring administrations to preserve their water catchment areas in order to reduce the risk of flooding in the capital.

[Theresia Sufa in Bogor contributed to the story.]