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Title :Groundwater flow system under a rapidly urbanizing coastal city as determined by hydrogeochemistry
Authors :Kagabu, Makoto
Shimada, Jun
Delinom, Robert M.
Tsujimura, Maki
Taniguchi, Makoto
Issue Date :4-Jan-2011
Citation jtitle :Journal of Asian Earth Sciences
vol. :40
no. :1
start page :226
end page :239
Abstract :In the Jakarta area (Indonesia), excessive groundwater pumping due to the rapidly increasing population has caused groundwater-related problems such as brackish water contamination in coastal areas and land subsidence. In this study, we adopted multiple hydrogeochemical techniques to demonstrate the groundwater flow system in the Jakarta area. Although almost all groundwater existing in the Jakarta basin is recharged at similar elevations, the water quality and residence time demonstrates a clear difference between the shallow and deep aquifers. Due to the rapid decrease in the groundwater potential in urban areas, we found that the seawater intrusion and the shallow and deep groundwaters are mixing, a conclusion confirmed by major ions, Br−:Cl− ratios, and chlorofluorocarbon (CFC)-12 analysis. Spring water and groundwater samples collected from the southern mountainside area show younger age characteristics with high concentrations of 14C and Ca-HCO3 type water chemistry. We estimated the residence times of these groundwaters within 45 years under piston flow conditions by tritium analysis. Also, these groundwater ages can be limited to 20 to 30 years with piston flow evaluated by CFCs. Moreover, due to the magnitude of the CFC-12 concentration, we can use a pseudo age-indicator in this field study, because we found a positive correlation between the major type of water chemistry and the CFC-12 concentration.
URL :http://www.sciencedirect.com/science/article/pii/S1367912010002312
Type Local :雑誌掲載論文
Publisher :Elsevier
Rights :© 2010 Elsevier Ltd.
URI :http://hdl.handle.net/2298/21383
Appears in Collections:Journal Article (Sciende)
Please use this identifier to cite or link to this item: http://hdl.handle.net/2298/21383