Yanita Petriella, Yanita Petriella, Jakarta – Throughout Tuesday March 4, the Greater Jakarta (Jabodetabek) area was paralysed by flooding. Some areas of Bogor and Bekasi regencies that are crossed by the Cikeas, Cileungsi and Bekasi rivers were even flooded with waters to a height of up to five meters.
This was because of the heavy rain that showered the area since Monday afternoon until Tuesday morning both in upstream and downstream areas caused a high river water debit.
The National Disaster Management Agency (BNPB) recorded that temporary data on the regions covered and the number of residents affected by floods and landslides in the Greater Jakarta area as of Tuesday was around 119,206 people.
Greenpeace Indonesia Forest Campaigner Muhammad Iqbal Damanik said that the floods that occurred on Tuesday in Jabodetabek, especially the most severe ones that occurred along the Cileungsi, Cikeas and Bekasi rivers, was due to land conversion.
"The Bekasi River watershed (DAS) covers 147,000 hectares but the forested (area) is only 1,700 hectares. The natural landscape has undergone many changes becoming a built up areas so the water absorption has been greatly reduced", he told Bisnis on Wednesday March 5.
According to Damanik, during the rainy season water runoff becomes very large causing rivers to exceed their capacity. This is exacerbated by bad spatial planning. "The upstream areas have been cleared plus the bad management of the DAS", he said.
He said that in the Babakan Madang and Sukamakmur districts, the function of the upstream Bekasi River watershed has shifted to becoming residential and built up areas. "In the Bekasi River DAS there is Sentul City, Summarecon, Hambalang, Indocement. The remaining forest only exists in Mount Pancar", he said.
Meanwhile according to Greenpeace data, deforestation of the Bekasi River watershed green area between 1990 and 2022 reached 23,600 hectares. "At present there are 1,700 hectares left. So, the DAS is the flow and catchment areas. Not just to the right and left of the river. If the DAS is poor runoff water goes directly into the river", he said.
Ideally, 30 percent of watershed areas should be forest cover. Damanik suggested that the government obey the regulations on 30 percent forest cover in watershed flow areas.
This is because the supervision of housing development must be in accordance with the carrying capacity. The impact of infrastructure development, especially housing in the watershed area, is different from non-watersheds areas so it must be tighter.
"This flooding is part of extreme weather or what is called hydrometeorological disasters. So the government must immediately implement a commitment to reduce its emissions", said Damanik.
Indonesian Forum for the Environment (Walhi) spatial and infrastructure campaign manager Dwi Sawung said that the floods that occurred in Jabodetabek, in addition to rainfall, were also due to massive land conversion in the upstream area.
In addition to this, many certificates have been issued for land that should not be used to be used as a location for housing development, despite regulations prohibiting this. These areas should be used to absorb water or function as catchment areas.
"It can be seen in plain view in Sentul, Cikeas, Cileungsi, Hambalang, all of them have been built up", she told Bisnis.
According to Sawung, the government should have a long-term comprehensive plan to deal with watershed areas that does not to follow the government's administrative limits. In addition, the government needs to evaluate housing permits and commercial areas in order to restore water absorption and retention.
"Then fixing drainage properly, not because of following developers or who is are willing to pay", said Sawung.
Trisakti University city planning observer Yayat Supriatna believes that the river capacity in several areas of Jabodetabek is unable to accommodate the high rainfall intensity. This is because the environmental conditions in Jabodetabek are getting worse because of a reduction in water catchment areas and an increase in residential areas.
He gave the example of the severe floods that occurred in the Bekasi area because of the Bekasi, Cileungs and Cikeas rivers were unable to accommodate the high water debit. "The area that is passed by the rivers, left and right is housing. There are no embankments and walls so that no one is able to anticipate the volume of large water", he told Bisnis.
In addition to this, there are still many buildings standing on the riverbanks because the price of land is fairly cheap. Then there is a lot of illegal activities such as filling in watershed areas that causes the narrowing of rivers.
He hopes that the regional governments in Jabodetabek can sit down together to map the areas affected by flooding. Then it is necessary to deal with spatial planning because the handling of floods in Jabodetabek cannot only be dealt with by just one region.
Supriatna added that it is also necessary to add more ponds, lakes and reservoirs to accommodate the overflow of river water so that it does not flood housing areas. "There is a need for absorption wells in house yards to absorb water", he said.
University of Indonesia environmental and climate change observer Mahawan Karuniasa said that the floods that have again occurred in Jabodetabek are due to urban spatial problems, including environmental management. This is because the protected zone to maintain forest cover or vegetation in the upstream watershed which functions to maintain water system have undergone many changes.
"This protected zone should be strictly guarded, not becoming a built up area", he told Bisnis.
Land permit audit
Meanwhile, West Java Governor Dedi Mulyadi said that the major floods occurred in Bekasi and Bogor are due to massive land conversion in Puncak.
He has asked the state-owned plantation company PT Perkebunan Nusantara (PTPN) to stop activities shifting the land functions in Puncak. From data he has obtained, the function of more than 1,000 hectares of tea plantations in Puncak Bogor have changed so that it has impacted on the ecosystem and increases the risk of disasters.
According to Mulyadi, since the Dutch colonial era, the planting of tea trees in the Puncak Bogor area was not only for economic interests but also as part of environmental conservation and protection.
The provincial government will also evaluate tourist attractions at the Bogor peak including those the belonging to the West Java government (BUMD) owned PT Jasa and Tourism (Jaswita).
Bogor Regent Rudy Susmanto said that they would be more selective in issuing permits, especially those related to the environment in Bogor regency.
"I have issued a new regional regulation (Perbup), today we will sign it, namely to revoke the entire licensing process to be returned to the regional head. We will take back the delegation of licensing from the respective regional work units (SKPD)", he said as reported by the state news agency Antara.
Deputy Minister of Public Works (PU) Diana Kusumastuti said the floods that occurred both in Puncak in the upstream areas as well as downstream were because the rivers were unable to accommodate the high intensity of rain fall that hit Bogor since Sunday March 2.
"I see that the rivers that were once wide, are now narrow because there are so many houses on the riverbanks. Water will of course find its own way, so my hope is, don't inhabit it", he said.
BNPB Disaster Information and Communication Data Centre head Abdul Muhari said that they will review the effectiveness of the Ciawi and Sukamahi dams in flood management. The Ciawi and Sukamahi Dams are dry dams built in Bogor regency to reduce flooding. The BNPB will also carry out weather modification on March 8.
[Abridged translation by James Balowski. The original title of the article was "Alih Fungsi Lahan Picu Banjir Bandang Lumpuhkan Jabodetabek?".]
