水文学・水資源

[II-69] Distribution of soil and geology in basin in relation to flood runoff flow discharge curve

〇Kazumasa Fujimura¹, Aki Yanagawa¹, Mashahiro Murakami³, Yoshihiko Iseri², Shoji Okada⁴, Shinjiro Kanae⁵ (1.Meisei University, 2.University of California, Davis, 3.Kochi University of Technology, 4.Kochi National College of Technology, 5.Tokyo Institute of Technology)

Keywords:flood runoff, soil, geology, flow duration curve, capacity of water retention of basin

Under situation of increasing of disaster by heavy rainfall, it is important to clarify the contribution of basin conditions to the flood runoff for flood control planning. Therefore, this study aims to represent factors of flood runoff related to basin condition of soil and geology, using 1 hour time step hydrological data over 14 years and GIS data of soil and geology, for 8 dam basins including snowy area. Flow duration curves under 1 percentile were normalized and approximated.

The results were shown, using the relative error R and the significance p as statistical methods, that the area ratio of brown forest soil, Tertiary strata, and Andosol / volcanic rock was related to flood runoff.