Study of Interaction of Shallow Groundwater and River along the Cisadane and Ciliwung River of Jakarta Basin and Its Management using Environmental Isotopes

The environmental isotopes were employed to study the interaction of shallow groundwater and river along the Cisadane River and Ciliwung River in Jakarta basin. The rapid growth and development of Jakarta and its surrounding cities, coupled with increasing industrial and other business sectors have impacted on the demand of the water supply for the area. These investigations have been conducted to determine the interaction between shallow groundwater and the river. The 14C results showed that the groundwater samples (above 40 m) which were close to the river influenced the iso-age contour of 14C, which indicated the contributions of river water. The analysis of stable isotopes 18O and Deuterium from the river implied that the river water from upstream to downstream was influenced by the mixing of the river water with the human activities in the upstream (the isotopic compositions becoming enriched). Further, the 18O and Deuterium data revealed that rivers of Cisadane and Ciliwung are contributing to recharge the shallow groundwater in Jakarta,
especially in the nearby river bank. In general, the quality of the shallow groundwater along the rivers is good and is suitable as fresh water resource. Due to pollution and declining water table problems in the Jakarta basin, the artificial recharge wells is shown to be a good way out to delineate the problems as indicated by pilot project conducted at Kelurahan Kramat Jati, using infiltration basin method.

Keywords : isotope, shallow groundwater, interaction, river, quality, groundwater management