TY - GEN
T1 - Simulation of large freshwater behavior in Hakata Bay due to torrential rain using nested two-dimensional model
AU - Fukuda, Akihiro
AU - Tabata, Toshinori
AU - Honda, Yuri
AU - Hiramatsu, Kazuaki
AU - Masayoshi, Harada
PY - 2018/9/1
Y1 - 2018/9/1
N2 - In this study, a numerical simulation consisting of a two-dimensional model of Hakata Bay, Kyushu Island. Japan, was conducted to analyze the impact oflarge river discharges due to torrential rain. Since Fukuoka city, one of the largest cities in Japan, surrounds Hakata Bay, the bay has a very complex environment, including an artificial island (Island City) in its eastern region and small bay (Imazu Bay) where tideland is spread with rich ecosystems in its western region. Tank models were applied to calculate the discharges of the 38 rivers that flow into Hakata Bay, and a two-way nesting technique, "edge nesting," was developed and applied in the model to capture the influence of complex geographical features, such as the Island City area and the Imazu Bay area, which were nested with a high-resolution mesh. The model accurately reproduced the observed tidal current and salinity data. To simulate the behavior oflarge river discharges, a historical simulation period including a torrential rain event (163.5 mm/d) was input into the model. The results showed that after the rain event, low-salinity water covered the entire inner part of Hakata Bay, and freshwater covered the entire area of the tidal flats and flowed out from the mouth of Imazu Bay. The behavior of this large mass of fresh water was remarkably different from usual discharge river flow. These results indicate that the environment in the bay can be significantly changed by torrential rain events.
AB - In this study, a numerical simulation consisting of a two-dimensional model of Hakata Bay, Kyushu Island. Japan, was conducted to analyze the impact oflarge river discharges due to torrential rain. Since Fukuoka city, one of the largest cities in Japan, surrounds Hakata Bay, the bay has a very complex environment, including an artificial island (Island City) in its eastern region and small bay (Imazu Bay) where tideland is spread with rich ecosystems in its western region. Tank models were applied to calculate the discharges of the 38 rivers that flow into Hakata Bay, and a two-way nesting technique, "edge nesting," was developed and applied in the model to capture the influence of complex geographical features, such as the Island City area and the Imazu Bay area, which were nested with a high-resolution mesh. The model accurately reproduced the observed tidal current and salinity data. To simulate the behavior oflarge river discharges, a historical simulation period including a torrential rain event (163.5 mm/d) was input into the model. The results showed that after the rain event, low-salinity water covered the entire inner part of Hakata Bay, and freshwater covered the entire area of the tidal flats and flowed out from the mouth of Imazu Bay. The behavior of this large mass of fresh water was remarkably different from usual discharge river flow. These results indicate that the environment in the bay can be significantly changed by torrential rain events.
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M3 - Conference contribution
AN - SCOPUS:85063991593
T3 - Proceedings - International Association for Hydro-Environment Engineering and Research (IAHR)-Asia Pacific Division (APD) Congress: Multi-Perspective Water for Sustainable Development, IAHR-APD 2018
SP - 521
EP - 529
BT - Proceedings - International Association for Hydro-Environment Engineering and Research (IAHR)-Asia Pacific Division (APD) Congress
A2 - Olii, Muhammad Ramdhan
A2 - Legono, Djoko
A2 - Hairani, Ani
A2 - Benazir, null
A2 - Warniyati, Warniyati
A2 - Setiawan, Hendy
A2 - Hambali, Roby
A2 - Ahmad, Johan Syafri Mahathir
A2 - Karlina, null
PB - Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada
T2 - 21st Congress of International Association for Hydro-Environment Engineering and Research-Asia Pacific Division: Multi-Perspective Water for Sustainable Development, IAHR-APD 2018
Y2 - 2 September 2018 through 5 September 2018
ER -