[A-HW20] Integrated Watershed Management under the Future Extreme Disaster

[AHW20-05] Integrated sediment experiment of Wushe Reservoir under extreme hydrological conditions

*Fong-Zuo Lee¹, Jihn-Sung Lai², Che-Min Liao³, Hsiu-Chin Tu⁴ (1.National Chung Hsing University, 2.National Taiwan University, 3.Sinotech Engineering Consultants, Ltd., 4.Taiwan Power Company)

Keywords:desiltation strategies, physical models, hydrological conditions

The conservation and sustainable operation of reservoir capacity is a critical concern under normal and extreme weather conditions. The sedimentation of a reservoir is influenced by geological and hydrological conditions, as well as reservoir operation. Therefore, an understanding of inflow, outflow, sediment dynamics, desilting capacity of discharge structures, reservoir operation objectives, and available desiltation methodologies is essential for assessing reservoir desiltation strategies. Valuable desiltation strategies and extreme hydrological conditions are examined through the analysis of capacity/inflow ratio (CIR) and capacity/sediment ratio (CSR) using physical models. In this study, the outlet elevation, block condition, and desilting efficiency of the desilting tunnel are explored using a distorted physical model. The hydraulic mechanism and sediment transport phenomenon are tested with a scale model. Additionally, the anti-vortex design of the desilting tunnel intake and the stilling basin geometry of the desilting tunnel outlet are studied to ensure effective operation. Sediment replenishment locations and outflow sediment transportation in the downstream riverbed are considered under various reservoir operations and hydrological conditions. The results from physical models indicate that the proposed sediment management desiltation strategies can achieve the expected effectiveness.