Japan Geoscience Union Meeting 2022

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[J] Oral

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

[A-HW26] Isotope Hydrology 2022

Wed. May 25, 2022 10:45 AM - 12:15 PM 105 (International Conference Hall, Makuhari Messe)

convener:Masaya Yasuhara(Rissho Univ.), convener:Shinji Ohsawa(Institute for Geothermal Sciences, Graduate School of Science, Kyoto University), Kazuyoshi Asai(Geo Science Laboratory), convener:Takashi Nakamura(International Research Center for River Basin Environment, University of YAMANASHI), Chairperson:Masaya Yasuhara(Rissho Univ.), Kazuyoshi Asai(Geo Science Laboratory), Takashi Nakamura(International Research Center for River Basin Environment, University of YAMANASHI), Noritoshi Morikawa(Geological Survey of Japan, AIST)

11:05 AM - 11:25 AM

[AHW26-02] Quantification of Dissolved Organic Carbon Sources and Flow Pathways during Storm Events by Using Carbon Isotope Technique in a Forested Watershed

★Invited Papers

*Kazunori Ebata1, Takashi Nakamura2, Kei Nishida2 (1.National Institute of Technology, Toyota college, 2.Interdisciplinary Centre for River Basin Environment, University of Yamanashi)

Keywords:Dissolved Organic Carbon, δ13CDOC, DOC source area, DOC runoff model

Estimation of dissolved organic carbon (DOC) runoff load in a forested watershed is important for global carbon cycle and local water management. We developed DOC runoff model from two nested study areas in Yamanashi, Japan based on DOC Source Area (DSA) concept by considering hydrological connectivity and topographic feature of the catchment. However, we have not yet quantified the DSA temporal variability. Hence, monitoring the δ13CDOC are useful tool as DOC pool fingerprints and to reveal the quantifying their relative contribution to stream DOC. By using EMMA, we showed each flow contribution to the DOC load and temporal variability at hourly base data and totally calculated six storm events as 63.4% to 80.3 %, 18.7 to 42.1% of surface layer contribution to DOC load at upperstream and downstream, respectively. In addition, surface layer contribution at upperstream was obviously larger than that at downstream because of the different topography and landscape between the two sites. Finally, we compare with both techniques as for isotopic EMMA and DOC runoff model, isotopic EMMA was supported DSA concept of DOC runoff model.