The Disappearance of Flood-Control Reservoirs in Jabodetabek, from Thousands to Just 187
JAKARTA – The number of situ (natural reservoirs) functioning as flood control mechanisms in the Jakarta, Bogor, Depok, Tangerang and surrounding areas (Jabodetabek) continues to decline significantly.
This phenomenon represents one of the primary factors contributing to the escalating flood threats currently afflicting the Jabodetabek region.
However, of the 187 remaining situ, not all continue to function as flood control mechanisms.
David Partonggo Oloan Marpaung, Head of the Ciliwung Cisadane River Basin Authority (BBWS Ciliwung Cisadane), confirmed the substantial reduction in the number of situ within his jurisdiction.
“Eighteen situ have already changed function, leaving 169 situ remaining. Meanwhile, in the DKI Jakarta region, the local government manages 16 situ, bringing the total number of situ still present in our working area to 185,” David stated in a written statement received by Kompas.com on Sunday (1 March 2026).
The gradual annual disappearance of situ across Jabodetabek has been driven by widespread land conversion and spatial planning alterations. Many reservoir areas have been filled in and transformed into dry land, subsequently developed into permanent built-up zones such as residential areas.
Consequently, water storage capacity has declined drastically. A notable example of this phenomenon is Situ Kuru in South Tangerang, whose area has shrunk dramatically from approximately 5 hectares to just 0.54 hectares due to utilisation of portions of the land for residential development.
The conversion of situ function into built-up zones is considered to have directly impacted the increasing potential and severity of flooding in Jabodetabek in recent times.
“Indeed, one cause of flooding is land conversion (of situ or reservoirs),” said David.
The first vital function that has been lost is that of water conservation area, where situ should serve to store water, facilitate infiltration processes, and maintain groundwater reserves for the long term.
The second function that has also disappeared is the situ’s role as a natural flood control mechanism.