Japan Geoscience Union Meeting 2015

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

[A-HW27] Water and material transport and cycle in watersheds: from headwater to coastal area

Sun. May 24, 2015 9:00 AM - 10:45 AM 301B (3F)

Convener:*Shinji Nakaya(Department of Civil Engineering, Faculty of Engineering, Shinshu University), Mitsuyo Saito(Graduate School of Environmental and Life Science, Okayama University), Shin-ichi Onodera(Graduate School of Integrated and Arts Sciences, Hiroshima University), Kazuhisa Chikita(Department of Natural History Sciences, Faculty of Science, Hokkaido University), Tomohisa Irino(Faculty of Environmental Earth Science, Hokkaido University), Masahiro Kobayashi(Forestry and Forest Products Research Institute), Seiko Yoshikawa(Narional Institute for Agro-Environmental Sciences), Noboru Okuda(Research Institute for Humanity and Nature), Chair:Tomohisa Irino(Faculty of Environmental Earth Science, Hokkaido University)

9:45 AM - 10:00 AM

[AHW27-04] Assessment of the impacts of abandoned cultivated land on material flux in hilly and mountainous watersheds

*Yuta SHIMIZU1, Shin-ichi ONODERA2, Kenji MATSUMORI3 (1.National Agriculture and Food Research Organization / JSPS Research Fellow, 2.Graduate School of Integrated Arts and Sciences, Hiroshima University, 3.National Agriculture and Food Research Organization)

Keywords:material transport, hilly and mountainous watersheds, SWAT model

Agricultural land-use has been reduced by mainly urbanization and devastation in Japan. The objective of this study is to evaluate the impact of the decline of agricultural land-use on flood risk and material flux in hilly and mountainous watersheds using Soil Water Assessment Tool. The results indicated that increase of flood risk due to abandonment of agricultural land-use. Furthermore, the abandonment of rice paddy field on steep slope areas may have larger impacts on sediment discharges than cultivated field. Therefore, it is suggested that prevention of expansion of abandonment of rice paddy field is an important factor in the decrease of yields of sediment and nutrients.