日本地球惑星科学連合2018年大会

講演情報

[EJ] Eveningポスター発表

セッション記号 H (地球人間圏科学) » H-CG 地球人間圏科学複合領域・一般

[H-CG24] 堆積・侵食・地形発達プロセスから読み取る地球表層環境変動

2018年5月20日(日) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:清家 弘治(産業技術総合研究所・地質調査総合センター)、山口 直文(茨城大学 広域水圏環境科学教育研究センター)、成瀬 元(京都大学大学院理学研究科、共同)、高柳 栄子(東北大学大学院理学研究科地学専攻)

[HCG24-P03] The Effect of Dam Removal upon Sediment Dynamics: Experiments of a Scale Model of Landao Creek Check Dam in Central Taiwan

*Yung-Ching Hsu1 (1.National Chung Hsing University)

キーワード:Dam removal, Laboratory experiment, Sediment Dynamics

Compared with a lot of conceptions and models established for dam removals in the United States, there are only a few cases about dam removals in Taiwan. Streams in Taiwan are characterized by steep slopes (3 to 7 degree) and very high discharge during rainfall season. Frequent earthquakes generate loose sediment on hillslopes. Abundant sediment from hillslopes and river banks enter into channels during typhoon events, resulting in full of sediment upstream of check dams. It is considered removing check dams because of losing their function of storing sediment. An open-type check dam located in Landao Creek which is a tributary of Beigang River in Central Taiwan was chosen as the model of the dam removal experiments. We built a scale model (1:50) of the dam in the laboratory. Bed materials were composed of three different sizes of particles (0.8, 0.5 and 0.1cm) with different combinations. Different types of removals were applied to discover the dam removal effect on extent of upstream erosion, changes of channel slope and particle sizes downstream the dam under the conditions of different discharges. After removing a part of the dam, the upstream sediment coarsened while the downstream deposits were fine and moderate sediment. The extent of reservoir erosion was closed related to the height of removals.