Lakes in Greater Jakarta Shrinking as Flood Control Reservoirs Decline from Thousands to 185

Jakarta – The number of natural lakes (situ) that function as flood control reservoirs in the Jakarta, Bogor, Depok, Tangerang and surrounding area (Greater Jakarta) continues to decline. This situation is considered to be exacerbating the flood risk that has been increasingly occurring in the region.

Data from the Water Resources Data Center (WRDC) indicates that of the thousands of lakes previously recorded, only 187 situ managed by the Large River Basin Agency (BBWS) Ciliwung Cisadane remain. Specifically in DKI Jakarta, only 16 situ locations are still preserved. Overall, the number of lakes currently under the supervision of BBWS Ciliwung Cisadane stands at approximately 185 situ after accounting for those that have changed function.

The shrinkage of situ in Greater Jakarta has been triggered by widespread land conversion and changes in spatial planning. Many lakes have been filled in and converted into dry land, then developed into residential areas. Consequently, water storage capacity has decreased significantly.

One example is Situ Kuru in South Tangerang. The size of this lake has shrunk dramatically from approximately 5 hectares to just 0.54 hectares. This reduction occurred because part of the lake area was used for residential development.

The conversion of lakes into residential areas is considered to have a direct impact on increasing the potential for flooding in Greater Jakarta in recent months. The loss of water retention capacity in natural lakes has weakened the ecosystem-based flood control system across Greater Jakarta.

As river discharge increases rapidly due to reduced natural storage, flooding is triggered downstream. With diminished water storage capacity in natural lakes, the ecosystem-based flood control system in Greater Jakarta has become increasingly compromised.