日本地球惑星科学連合2018年大会

講演情報

[EJ] 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) 13:45 〜 15:15 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-P04] Erosion characteristics in a shallow water area covered with rigid emergent macrophytes

Yung-Chieh Wang1、*DENG-YONG CHEN1 (1.National Chung Hsing University)

キーワード:rigid emergent macrophytes, scouring experiments

In recent years, riparian zones by riverside have been remediated by revegetation for the purpose of erosion control, rather than by engineering measures such as concrete revetment. Therefore, it is essential to understand the reaction to shallow water scouring of rigid emergent macrophytes and fitness of the plants in riparian zones. In the past, artificial materials such as acrylic cylinders were mostly used as surrogate plants. However, such materials could neither simulate the protecting function provided by the root system against scouring, nor test the survival rate of plants during floods. In this study, we selected four true emergent macrophytes and planted them in a regular array in a recirculating flume for scouring experiments. Each plant was cultivated in the flume under the low-discharge condition in the first month in order to make its root system develop in the soil. Then we increased the discharge gradually for every two weeks during the following two months. Before the discharge was increased each time, the topographic change and erosion amount through the planted- and unplanted-areas were obtained by the laser scanning leaf topography method and the image analysis technique. The growing conditions of the macrophyes were also recorded weekly. From the results, we found that scouring occurred in the channels among stems of macrophytes, and the sediments mostly accumulated around and behind the stems in the planted-area. The phenomenon seemed different from cylinder simulations in the literature, whose results pointed that the flow around a cylinder would cause deep scours while channels between any two cylinders should be accumulation zones at low discharge.