Groundwater Studies in Jakarta and Its Vicinity. Part of Coordinated Programme on Application of Environmental Isotope Techniques of Groundwater Problems. Final Report for the Period 1 July 1980-31 March 1985

摘要

Groundwater from an unconfined and two underlying confined aquifers was sampled from 97 locations in the Jakarta area and analysed for deuterium, oxygen-18, tritium, carbon-14, carbon-13 and chemical composition. The stable isotopic composition of groundwater is more depleted with increase in depth. The variance decreased with increase of depth with the result that the deepest confined aquifer has the most homogeneous stable isotopic composition. The presence of more depleted waters in the shallower waters, thus giving rise to the greater variance in the upper aquifers, is interpreted as being due to upward leakage from the deeper aquifer. Little or no tritium was found in the confined aquifers, while the presence of tritium in some samples from the unconfined aquifer is indicative of recharge by infiltration from streams and of local precipitation. Carbon-14 data from the confined aquifers indicate groundwater movement from south to north-east and estimated times since recharge of the order of 30,000 years in the lower part of the basin. (Atomindex citation 17:002149)