Updated subsidence scenarios Jakarta : MODFLOW SUB-CR calculations for Sunter, Daan Mogot and Marunda

Since 2015 modelling is conducted to provide forecasts of the subsidence that should be anticipated at three locations in northern Jakarta (Daan Magot, Sunter, Marunda) under different scenarios of groundwater use. The resulting subsidence scenarios are essential for the planning of the integrated measures to protect the city against marine and riverine flooding. This report provides an update of prior work. The main objective of the work was to shed light on the confidence level of the prognoses. Calculations were done using MODFLOW in combination with the Deltares-developed SUB-CR package. Results that are presented in tables and figures are of value to set realistic bounds (upper and lower limits) to the subsidence scenarios. This is important for both flood defence measures and subsidence monitoring. The results confirm the conclusion of prior work that it may take up to about two decades for groundwater-extraction-induced subsidence to stop after groundwater extraction stops. The analysis also shows that the uncertainty in this prognosis is large.