Modelling for Groundwater Extraction Effect for Jakarta Land Subsidence

Subsidence has been a very disturbing issue as its endangered densely populated area at the north part of Jakarta as well as the infrastructure that existed along the coastline. Although there are several main coause of subsidence in Jakarta, discussion will be from the groundwater effect point of view. The subsidence has become a consideration for Jakarta to build a preventive infrastructure or any other infrastructure in Jakarta. Due to Subsidence process, there are some consequences has to be bare such as building damages and flooding that has become fidgety for people along the coastline. Today the sea level has become higher than houses along the shoreline. The research conducted in Sunter area that has been completed with sufficient geotechnical data with groundwater level measurements from 1985 and geodetic measurements since 1985. Based on the data, the rate of subsidence calculated as settlement and calibrated with Geodetic GPS measurements. As the result, the rate of subsidence for existing condition is not affected by the rate of groundwater level decreasing during 1985 to 2015 around 0.3 meters/year. Modelling continues using an extreme scenario that reaches 1.5 meters/year and the result is ground water has a significant effect on subsidence. The percentage of the groundwater effect of subsidence in normal condition is less than 5 %, but in extreme condition is around 30 %.