Japan Geoscience Union Meeting 2015

Presentation information


Symbol A (Atmospheric and Hydrospheric Sciences) » A-HW Hydrology & Water Environment

[A-HW25] Groundwater and environmental geology in urban areas

Wed. May 27, 2015 2:15 PM - 4:00 PM 101B (1F)

Convener:*Masaya Yasuhara(Geological Survey of Japan, AIST), Takeshi Hayashi(Faculty of Education and Human Studies, Akita University), Motoyuki Asada(Shimizu Corporation), Satoshi Takizawa(Department of Urban Engineering, Graduate School of Engineering, the University of Tokyo), Hiroaki SUZUKI(Strategic Technology Development Dept. Research & Development Center, Nippon Koei Co., Ltd.), Kei Nishida(Interdisciplinary Graduate School of Medicine and Engineering, the University of Yamanashi), Chair:Kei Nishida(Interdisciplinary Graduate School of Medicine and Engineering, the University of Yamanashi), Masaya Yasuhara(Geological Survey of Japan, AIST)

2:35 PM - 2:50 PM

[AHW25-02] Ammonium sources of groundwater in Kathmandu Valley, Nepal

*Takashi NAKAMURA1, Kei NISHIDA1, Yuki YAMAMOTO2, Kodai HIRAGA2, Anoj Khanal3, Suresh Das Shrestha3, Futaba KAZAMA1 (1.ICRE, University of Yamanashi, 2.faculty of eng., University of Yamanashi, 3.CDG, Tribhuvan University)

Keywords:Kathmandu, Urban, Groundwater, Nitrogen isotope in ammonium, Nitrogen and oxygen isotope in nitrate

Groundwater quality is a critical problem in the Kathmandu Valley, Nepal. The population of the city increased by 6 times in the last six decades and more than half of water demand depends on groundwater source. Microbial and nitrogen contamination causes loss of water resources, nevertheless, understanding of nitrogen source and dynamics in groundwater system still remains insufficient in the central area of the valley. Objective of this study is to identify source of ammonium contamination on shallow and deep groundwater.
Groundwater samples were collected from 34 shallow wells and 5 deep tube wells in September 2014. Ammonium ion were detected from 12 shallow wells and 2 deep wells. Those ammonium concentrations ranged from 1.3 to 103 ppm. Nitrogen isotope values in ammonium ranged from -0.3 to 9.3 permill; this wide range of the nitrogen isotope values suggested possibility of ammonium contamination from natural and anthropogenic sources.

This study are supported by the Science and Technology Research Partnership for Sustainable Development Program (SATREPS, Project Manager: Prof. Narendra Man Shakya and Prof. Futaba Kazama) of Japan Cooperation Agency (JICA)/Japan Science and Technology Agency (JST).