| 研究実績の概要 |
During FY2022, we utilized an integrated surface-subsurface flow modeling approach to evaluate the effectiveness of drywells in reducing urban runoff at a catchment scale. A 3D model with HydroGeoSphere was developed, characterizing a synthetic unconfined aquifer covered by a layer of low-permeability materials. Sensitivity analyses of parameters such as land surface conditions, aquifer properties, drywell designs, and rainfall conditions were performed. Model results indicated that drywells are more effective in reducing runoff when the land surface has a higher Manning roughness coefficient or the aquifer material has a higher hydraulic conductivity. To achieve optimal performance, drywells should be situated beneath drainage routes that have high runoff flux. Increases in drywell radius or depth enhance the infiltration capacity, but deeper drywells can contaminate groundwater through infiltrating stormwater. Drywell performance declines with higher rainfall intensity, emphasizing the need for local rainfall intensity, duration, frequency (IDF) data to inform the design level of drywells in specific catchments
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| 今後の研究の推進方策 |
The proposed modeling approach is scheduled to be applied to a real-world site, specifically Koganei City, Japan. The model will play a crucial role in analyzing the impact of installed drywells on groundwater storage and their efficacy in controlling urban flooding. The results of this analysis will be presented at the International Association of Hydrogeologists (IAH) meeting and submitted to a reputable journal to be shared with the wider scientific community. The outcomes of this research are expected to provide valuable insights into improving urban water management and flood prevention strategies.
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