Methods for verification of groundwater flow simulators (case study: Jakarta groundwater basin in the urban villages of Jatiluhur and Jatirangga, Bekasi City)

Limited access to clean water leads to residents extracting groundwater through dug wells or boreholes, which in turn results in groundwater becoming contaminated. Groundwater flow simulation of the Jakarta basin, which has been previously modeled with the Groundwater Modeling System 10.3, can be used as a basis for simulating groundwater flow pollution. Before simulating the groundwater flow pollution, the groundwater flow simulator needs to be verified to examine whether simulators and conditions in the field correspond to the water table level. This study demonstrated the methodology used for verification of the simulator in research. Verification was done using the Chi-square method. The results revealed that calculated Chi-square values were larger than Chi-square table values for the two urban villages of Jatiluhur and Jatirangga. The value of calculated Chi-square value for Jatiluhur was 17.3, whereas it was 7.81 in the Chi-square table. In Jatirangga, the calculated Chi-square value was 37.23, whereas it was 14.1 in the Chi-square. Results indicated that the simulation was not in accordance with the actual water table level. This discordance can occur since it necessary to update the data on groundwater flow simulation results with bore log data or to verify the hydrodynamic conditions of the study area.