17:15 〜 19:15
[AHW22-P09] Visualization of Regionalized Unstable Sediment Risk Distribution under Climate Change Impact: A Case Study of Zengwen Reservoir, Taiwan
キーワード：SWAT Model, Climate Change, Unstable Sediment, Risk Analysis
Taiwan faces water resource scarcity, making reservoirs crucial for water supply. Despite significant investment in desilting operations each year, the effectiveness remains limited. Additionally, climate change in recent years has triggered numerous sediment-related disasters, exacerbating the burden on reservoirs. This study aims to analyze sediment management in upstream reservoir catchment areas to mitigate sediment inflow into reservoirs. This study also integrates the SWAT (Soil and Water Assessment Tool) model with a risk-based hierarchical approach to achieve informatized sediment analysis in the catchment area. It incorporates climate change and unstable sediment impact assessments, providing diverse risk management tools and basis of decision-making for management authorities.
The study consists of two main parts. First, by applying SWAT model to analyze sediment transport in Zengwen Reservoir catchment area. The SWAT model employs a governance unit-based approach, dividing the catchment into multiple sub-watersheds using hydrological nodes for improved accuracy. The model's unique Hydrologic Response Unit (HRU) concept classifies regions with similar land use, soil types, and slopes into the same HRU, assuming uniform hydrological behavior within each unit. Through this approach, hydrological processes in different HRUs within a sub-watershed are independently calculated and aggregated at the sub-watershed outlet to obtain overall output. Second, by conducting risk analysis based on the model simulation results. The HRU calculations enable a regionalized assessment of sediment issues in each sub-watershed within the reservoir catchment area. A risk map is generated to visually present each individual sub-watershed sediment budget risk distribution.
Furthermore, by incorporating climate change scenarios from AR6 (Sixth Assessment Report), sediment and risk variations under different climate conditions are compared, and percentage changes are statistically analyzed to propose management recommendations and strategies. Additionally, the impact of unstable sediment is considered to estimate the risk of unstable sediment under extreme climate conditions in each sub-watershed. Corresponding risk maps are generated to provide comprehensive risk information for future reservoir upstream catchment sediment. management usage.
The study consists of two main parts. First, by applying SWAT model to analyze sediment transport in Zengwen Reservoir catchment area. The SWAT model employs a governance unit-based approach, dividing the catchment into multiple sub-watersheds using hydrological nodes for improved accuracy. The model's unique Hydrologic Response Unit (HRU) concept classifies regions with similar land use, soil types, and slopes into the same HRU, assuming uniform hydrological behavior within each unit. Through this approach, hydrological processes in different HRUs within a sub-watershed are independently calculated and aggregated at the sub-watershed outlet to obtain overall output. Second, by conducting risk analysis based on the model simulation results. The HRU calculations enable a regionalized assessment of sediment issues in each sub-watershed within the reservoir catchment area. A risk map is generated to visually present each individual sub-watershed sediment budget risk distribution.
Furthermore, by incorporating climate change scenarios from AR6 (Sixth Assessment Report), sediment and risk variations under different climate conditions are compared, and percentage changes are statistically analyzed to propose management recommendations and strategies. Additionally, the impact of unstable sediment is considered to estimate the risk of unstable sediment under extreme climate conditions in each sub-watershed. Corresponding risk maps are generated to provide comprehensive risk information for future reservoir upstream catchment sediment. management usage.