2021 Fiscal Year Annual Research Report
Environmental assessments of aquifer storage and recovery for decentralized wastewater management
| Project/Area Number |
21F21787
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| Research Institution | The University of Tokyo |
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Principal Investigator |
徳永 朋祥 東京大学, 大学院新領域創成科学研究科, 教授 (70237072)
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| Co-Investigator(Kenkyū-buntansha) |
LIU JIAQI 東京大学, 新領域創成科学研究科, 外国人特別研究員
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| Project Period (FY) |
2021-09-28 – 2024-03-31
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| Keywords | drywell / aquifer recharge / urban runoff |
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| Outline of Annual Research Achievements |
During FY2021, a series of numerical simulations were conducted based on a conceptual unconfined aquifer to investigate the performance of drywells for aquifer recharge and flooding control in urban areas. Numerical simulations were conducted using a coupled surface-subsurface flow modeling approach. A modeling strategy was developed that could explicitly describe the drywell geometry in the model domain. Sensitivity analysis were conducted to explore to the effects of parameters including drywell designs (location, depth, radius, and number), aquifer properties (hydraulic conductivity and its heterogeneity), and rainfall patterns (intensity and duration). Results showed that installing drywells can enhance groundwater recharge and reduce urban runoff during heavy rainfall events. The infiltration capacity of drywells were found to depend on two factors, initial storage and infiltration, which can be affected by drywell designs and aquifer properties in different ways under different rainfall scenarios.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The numerical experiments conducted in FY2021 provided a fundamental understanding of drywell performance for enhancing aquifer recharge and mitigating urban runoff, which will benefit the design and data analysis of real-world case studies in the next research stage. The developed conceptual model will serve as a basis for integrating with reactive mass transport modeling in the next research stage.
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| Strategy for Future Research Activity |
The research activities in FY2022 will focus on two targets:
(1) The coupled surface-subsurface flow model developed in FY2021 will be integrated with reactive mass transport modeling techniques in order to understand the impacts of drywells on groundwater quality and elaborate relevant hydrogeochemical processes.
(2) The developed numerical modeling strategy based on the conceptual aquifer will be applied to a realistic field case, Koganei City, Japan, in order to assess the performance of installed drywells for aquifer recharge. Fieldwork will be conducted to install sensors in existing drywells and monitoring wells for collecting information on infiltration rate and groundwater level dynamics.
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