Title: Comparison of isotope analysis and tank model calculation method to determine the snowmelt water ratio in river water

Authors: Shigeki Harada; Taisuke Hashimoto; Taisuke Sato

Addresses: Department of Environmental Sciences, School of Food, Agricultural and Environmental Sciences, Miyagi University, 2-2-1 Hatadate, Taihaku-ku, Sendai 982-0215, Japan ' Department of Environmental Sciences, School of Food, Agricultural and Environmental Sciences, Miyagi University, 2-2-1 Hatadate, Taihaku-ku, Sendai 982-0215, Japan ' Department of Environmental Sciences, School of Food, Agricultural and Environmental Sciences, Miyagi University, 2-2-1 Hatadate, Taihaku-ku, Sendai 982-0215, Japan

Abstract: Isotope analysis of river water can be used to evaluate the contribution of snowmelt water in rivers because snow (precipitation) has relatively higher δ¹⁸O-NO₃. Quantitative determination of snowmelt water input is needed for catchment environmental planning, agricultural planning and water resources planning in heavy snow regions, such as Miyagi Prefecture in Tohoku, Japan. We compared the measured δ¹⁸O-NO₃ values in the Okura River (Sendai, Miyagi Prefecture) in the snowmelt seasons of 2013 and 2014 with the snowmelt water ratio calculated by the tank model for the years 1985 to 1989 and reported in Kato and Kurashima (1998). Although the seasonal periods of δ¹⁸O-NO₃ measurements were not identical with the earlier period, with consideration of the meteorological conditions, variation in δ¹⁸O-NO₃ was well explained by the contribution of snowmelt water to the river determined by the tank model. Thus, measured δ¹⁸O-NO₃ could be used for catchment environmental planning in the region. This case study demonstrates the potential use of δ¹⁸O-NO₃ values for determining the snowmelt water ratio in other rivers.

Keywords: snowmelt water ratio; stable isotope ratio; tank models; heavy snow areas; meteorological conditions; Okura River; Japan; river water; nitrate; oxygen-18; delta-O-18; catchment environmental planning; agricultural planning; water resources planning.

DOI: 10.1504/IJHST.2017.080955

International Journal of Hydrology Science and Technology, 2017 Vol.7 No.1, pp.1 - 11

Received: 14 May 2015
Accepted: 29 Dec 2015
Published online: 13 Dec 2016 *

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