2017 Fiscal Year Annual Research Report
Modelling "non-wedge-shaped" groundwater-seawater interactions under climate change and urbanization impacts and its implications for coastal development at the inner Tokyo Bay Area
| Project/Area Number |
17J03852
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Liu Jiaqi 東京大学, 新領域創成科学研究科, 特別研究員(DC1)
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| Project Period (FY) |
2017-04-26 – 2020-03-31
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| Keywords | Revised / Numerical Model / Niijima Island / Kujukuri Plain / Coastal Progradation / Conceptual Model |
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| Outline of Annual Research Achievements |
Project 1: Aiming at improving the reliability of the modeling results, the 2-D numerical model that developed in the previous work was revised. The 2-D model simulated tsunami-induced seawater intrusion and aquifer recovery process in Niijima Island.
Project 2: A vertical 2-D numerical model of the coastal groundwater system at the Kujukuri Plain was developed. Assuming the coastal progradation during 5 ka to 4 ka completed instantly, the numerical model simulated the dynamics of GSIs during this period.
Project 3: A vertical conceptual numerical model with a field scale of 300 m × 20 m (length × height) was developed. A total number of 89 simulation cases under various conditions were designed and simulated.
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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 objectives are: 1) to understand the formation mechanism of nws-GSIs (non-wedge-shaped groundwater-seawater interactions) in the Tokyo Bay Area; 2) to assess the impacts of GSIs dynamics on future coastal development. To analyze nws-GSIs, first it is necessary to establish an adequate understanding of each single factor. Therefore, two coastal areas in Japan were selected as the representative cases for studying the two factors: the Niijima Island for the factor of tsunami disasters (Project 1), and the Kujukuri Plain for the factor of coastal progradation (Project 2). Also, a conceptual model of variable density flow and mass transport in an unsaturated-saturated aquifer was developed (Project 3).
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| Strategy for Future Research Activity |
Project 1: The lack of information on the groundwater salinity distribution at the coastal areas limits the reliability of the numerical model. To obtain the groundwater salinity data, a resistivity survey on the Niijima Island has been planned to be carried out during June 16-22, 2018. The data obtained from this survey is also expected to be used for confirming the bedrock surface elevation. The 3-D model in the previous work will be revised.
Project 2: A 3-D numerical model is planned to be developed to analyze the influence of tidal activities on GSIs in the next year of funding;
Project 3: A manuscript of this project is now under preparation and is planned to be submitted for publication in the next fiscal year.
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