10:00 AM - 10:15 AM
[AHW24-04] Identification of deep groundwater recharge system in an intermontane basin
Keywords:Groundwater recharge, water quality, Hydrogen and oxygen stable isotope, Radiocarbon, Kathmandu Valley, Nepal
Groundwater ion composition using Hexa-diagram showed that the deep groundwater of the Kathmandu Valley tends to be relatively young in the outer peripheral area. Meanwhile for the groundwater located in the central area tends to be older. However, for the shallow wells located at the central area, the higher values of ion composition were derived from the effect of human activities. Relatively high pMC values obtained from radiocarbon were detected from the shallow groundwater at central part of the valley and from the deep groundwater samples those were collected from the peripheral area. On the other hand, the deep groundwater at the central part of valley was observed with low pMC values.
Relatively heavier stable isotopes of hydrogen were observed from both the deep groundwater and the shallow groundwater in the central part of the valley. Along with the pMC values, these results also suggests the possibility of vertical groundwater recharge from the shallow groundwater to the deep groundwater in central part of the valley. However, isotopically depleted groundwater recorded from the peripheral areas also concludes the recharge in this basin occurs from the mountain areas.
AKNOWLEDGMENTS: This study was supported by the JSPS KAKENHI Grant Number is 18K11617. It was also partly supported by the Science and Technology Research Partnership for Sustainable Development Program (SATREPS, Project Manager: Professor Narendra Man Shakya and Professor Futaba Kazama) of the Japan International Cooperation Agency (JICA)/Japan Science and Technology Agency (JST).