Japan Geoscience Union Meeting 2018

Presentation information

[EJ] Oral

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

[A-HW23] Residence time of groundwater / surface water and water / mass cycle processes in watershed

Thu. May 24, 2018 9:00 AM - 10:30 AM 106 (1F International Conference Hall, Makuhari Messe)

convener:Maki Tsujimura(Faculty of Life and Environmental Sciences, University of Tsukuba), Shigeru Mizugaki(PWRI Public Works Research Institute), Masanori Katsuyama(京都大学農学研究科, 共同), Maksym Gusyev(International Centre for Water Hazard Risk Management, Public Works Research Institute), Chairperson:Gusyev Maksym, Katsuyama Masanori

9:20 AM - 9:35 AM

[AHW23-02] Integrated study on spatiotemporal variation of residence time in spring and groundwater at headwater catchments

*Maki Tsujimura1, Koichi Sakakibara1, Masanori Katsuyama2, Shigeru Mizugaki3, Maksym Gusyev4, Chsato Yamamoto1, Ayumi Sugiyama1, Mahiro Ogawa1, Kenji Kato5, Takuya Yamada2, Shinjiro Yano6, Naoya Sasakura6, Morgenstern Uwe7, Michael Kilgour Stewart7 (1.University of Tsukuba, 2.Kyoto University, 3.Civil Engineering Research Institute for Cold Region, 4.ICHARM, 5.Shizuoka University, 6.Suntory Global Inovation Center, 7.GNS Science, New Zealand)

Keywords:residence time, groundwater, spring water, headwater catchment

We performed an investigation on spatial and temporal variation of residence time in spring water and groundwater using SF6, CFCs, and microbe, and an evaluation of groundwater storage volume based on water budget analysis in multiple headwater catchments underlain by different lithology. Also, we investigated a temporal variation of residence time and the microbe information in spring water at a small forested headwater catchment underlain by granite, Fukushima, Japan.

The spring water age ranges from less than one year to more than 20 years, and the storage volume of the groundwater ranges from 103 m3 to 106 m3 in volume in the headwaters in Japan. The age of the spring water varies from less than one year to more than 10 years, and it tends to show high values specifically during the rainstorm events, whereas that is lower than 10 years during the rainless periods. Also, during the rainless periods, the age of the spring water is younger in the high flow rate, whereas that is older in the low flow rate. During the rainstorms, the age of the spring water is older in the high flow rate as compared with that in the low flow rate.

In the groundwater and the spring water at the hillslope scale, the age becomes younger, the total number of the prokaryotes becomes smaller, and the microbial diversity becomes higher from the ridge toward to the valley, from the recharge area to the discharge area, considering the groundwater flow system. From the viewpoints of the multiple headwater catchments, the microbial diversity tends to be lower in the spring water with the longer residence time.
The microbial information in quantity and quality is affected by the groundwater flow system in addition to the biological environment, and the microbe information would be possibly used as the tracer of the groundwater flow.