Jakarta-Ministry of Environment and Forestry (KLHK), Tuesday, January 7, 2020. One of the flood mitigation efforts in the Jakarta Bogor area Depok Tangerang and Bekasi or Jabodetabek, KLHK will improve forest rehabilitation in the upper watersheds (DAS), especially the Ciliwung watershed and the Cisadane watershed. Of the 8 watersheds that have led to flooded areas some time ago, the two watersheds were dominant because of the flooding, as well as the Bekasi River Basin.
Flooding occurred on January 1, 2020, with affected areas of Jakarta, Bogor, Depok, Tangerang, and Bekasi. Flood locations include downstream of the 8 watersheds, namely the Kali Angke Pesanggrahan watershed, the Krukut River watershed, the Ciliwung watershed, the Sunter watershed, the Buaran River watershed, the Cakung watershed, the Bekasi River watershed and the Cisadane watershed. Floods that occur are due to extreme rainfall which occurred since 31 December 2019.
“We will also immediately make Soil and Water Conservation (KTA) buildings such as retaining dams, controlling dams, and gully plugs as much as possible in the near future in the upstream area,” said Acting. Director-General of Watershed Management and Protected Forests (PDASHL) Hudoyo, during a Press Conference in Jakarta, Tuesday (07/01).
Besides the watershed conditions, extreme rainfall and land-use change, it is also suspected to have caused flooding. “After we check in the field or satellite imagery, most of the upstream land cover is dryland agriculture, which is vegetables. “In addition, most of the situ and swamps in Bekasi and surrounding areas have all been covered with concrete, in addition to a disturbing drainage system,” he said.
Therefore, for rehabilitation in other use areas (APL), KLHK expects the role of local government and the greater community to encourage rehabilitation of the area.
Furthermore, Hudoyo said the flooding was not a new problem for Jakarta, because naturally there are waterways from Bogor and Depok and the slopes of the Ciliwung watershed are alluvial fans which are clay soils that are easy to drain water.
Hudoyo conveyed the conclusions of the causes of Jakarta floods, including high to extreme rainfall, runoff from Bogor and Depok, the foot slopes of the alluvial fan of the Ciliwung watershed, loss of situ and swamp function conversion, land cover in the upstream area dominated by dryland agriculture (vegetable- vegetables) and the affected areas are dominated by built-up land so that surface runoff is high and infiltration is low, the drainage system is not able to anticipate extreme water volume increases and cultural problems disposing and managing poor waste.
Other factors that cause flooding are the low condition of waste management, as well as the presence of Illegal Final Processing Sites (TPA) and Open Dumping Landfill Management in several Jabodetabek areas. The three regions with the highest percentage of unmanaged waste are Bogor Regency (93.42%), Bekasi City (75.72%), and Bogor City (75.51%).
Waste that is not managed, in addition to polluting the environment and most likely will enter the body of water including drainage and even rivers. This makes the capacity of water capacity decreases and causes flooding.
Therefore, the Director-General of Law Enforcement of LHK Ratio Ridho Sani said KLHK will enforce the law firmly and consistently against managers and/or those responsible for waste management and/or activities that do not follow the legislation, norms, standards, procedures, or criteria which can cause public health problems, security problems, environmental pollution, and/or environmental damage.
“We enforce this law from upstream to downstream, as an effort to provide a deterrent effect, change behavior, and form a culture of obedience. We have also formed a task force to identify waste management points that are not in accordance with procedures, “said Ratio Sani.
Previously in 2019, the Directorate General of LHK Law Enforcement had held illegal landfill sealing in a number of points in Bogor, Tangerang, and Bekasi. Meanwhile, as a law enforcement step in the upstream sector, the Directorate General of Law Enforcement of the Environment and Forest Management conducts control of illegal mining activities that threaten watersheds.
Furthermore, the Director of Planning and Evaluation of Watershed Control (PEPDAS) Saparis Soedarjanto added a technical study that the “Land System” map scale of 1: 250,000 showed that most of Jakarta were categorized as an inundated land system, so it was a depression area storage). These conditions cause insufficient water energy to flow to a lower place towards the sea. If the momentum coincides with an increase in sea level and causes backflow to the land (known as tidal flooding), it will double the intensity of the flood. Floods in the early morning hours until the morning of January 1 reinforced this argument, because during this phase of time there was an increase in sea levels.
Rain patterns have changed to become very unfriendly towards Jakarta. High rainfall in the peak and upstream areas 13 The Watershed (DAS) has begun to change, tending to be spread evenly downstream. Extreme rain on January 1, 2020, with an intensity of 377 mm/day in the Halim area further legitimizes the changing and more evenly distributed rain patterns in the Jakarta area.