Development of Advanced Sediment Replenishment Methodology for Bedload Continuity below Dams

另外安装两个IP摄影机，一个在桥上，另一个在河的左岸，监测沉积物补充地点的实时泥沙侵蚀模式和SR地点附近的地表流速。另外，安装一个浊度计来测量悬浮沉淀物浓度。在Naka河进行了四次实地调查，测量了四个沙砾坝的粒度分布（GSD），用无人机测量了沉积物补给点，以及形态变化。法国比埃奇河的实地考察和资料收集。考虑纳卡河和布加勒斯特河补沙效率和下游生态水文地貌影响，建立纳卡河和布加勒斯特河补沙综合评价方法。基于TELEMAC-2D软件和Gaia软件，建立了纳卡河实施SR后水文形态变化的二维模拟模型。然后，针对之前的洪水事件和2022年的洪水事件，对该模型进行了校准和验证。在此基础上，利用该模型模拟了不同情景，研究了考虑补给侵蚀和下游响应的SR优化策略。长谷口大坝最近发生了罕见的大洪水，这表明在大坝管理下，增加冲洪幅度是很难实现的。

Installation of additional monitoring systems of two IP Cameras, one on the bridge and one on the left bank of the river, for real-time sediment erosion patterns at the sediment replenishment site and surface flow velocities near the SR site. Additionally, install one turbidity meter to measure suspended sediment concentration. In total, four times field surveys at Naka River for measuring Grain Size Distribution (GSD) along four gravel bars, a drone for the sediment replenishment site, and morphological changes. Field visit and data collection of Buech River in France. Develop a comprehensive assessment method for sediment replenishment in the Naka and Buch Rivers, considering the erosion efficiency of replenished sediment and downstream eco-hydro-geomorphological impacts. We established a two-dimensional model to simulate the hydro-morphological changes with the implementation of SR in the Naka River based on TELEMAC-2D coupled with Gaia. The model was then calibrated and validated for previous flood events and the 2022 flood event. Then, based on the calibrated model, we utilized it to simulate several scenarios to investigate the optimization strategies of SR by considering replenishment erosion and downstream responses. There are rare significant floods that occurred recently in the Nagayasuguchi dam, indicating that an increase in flushing magnitude is difficult to implement under dam management.