[A-HW27] 流域の水及び物質の輸送と循環－源流域から沿岸域まで－

[AHW27-04] 中山間地流域における物質輸送に及ぼす耕作放棄地の影響評価

*清水 裕太¹、小野寺 真一²、松森 堅治³ (1.(独)農研機構　近畿中国四国農業研究センター・日本学術振興会特別研究員PD、2.広島大学大学院総合科学研究科、3.(独)農研機構　近畿中国四国農業研究センター)

キーワード：物質輸送, 中山間地流域, SWATモデル

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.