Determination of Flow Characteristics of Ohashi River through 3-D Hydrodynamic Model under Simplified and Detailed Bathymetric Conditions
Marine Pollution Management Group, Port and Airport Research Institute Japan, 3-1-1 Nagase, Yokosuka 239-0826, Japan
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Academic Editors: Jiabi Du and Jian Shen
Water 2021, 13(21), 3076; https://doi.org/10.3390/w13213076
Received: 28 September 2021
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Revised: 20 October 2021
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Accepted: 29 October 2021
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Published: 2 November 2021
(This article belongs to the Special Issue Salt Intrusion in Coastal Areas)
The Ohashi River is a narrow water stream that connects two brackish lakes in Japan. Intermittent saline water intrusion often occurs in Lake Shinji from Lake Nakaumi through Ohashi River. In this study, two approaches were discussed to reproduce the hydrodynamic conditions of a morphologically complex river. In the first approach, the river sinuosity was straightened. The straightening of the river resulted in a higher flow velocity and water flux coefficient due to the reduction in the flow path and the resistance, and this approach was found to be appropriate for the reproduction of the flow velocity. However, the river shape was visually quite different from the actual river morphology. In the second approach, the prime focus was given to the shape and bathymetry to quantitively reproduce the flowrate of the saline water intrusion. This approach resulted in an underestimation of the flow velocity, which was compensated by increasing the cross-sectional area of the river. A slower flow velocity causes up to a 3-h time lag for the water mass to pass through the Ohashi River, which in principle should affect the temporal variations of the water temperature and salinity. Fortunately, as the typical time scale for water temperature and salinity fluctuations in the Ohashi River is a few days, a 3-h time lag did not cause any problems.
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MDPI and ACS Style
Hafeez, M.A.; Inoue, T. Determination of Flow Characteristics of Ohashi River through 3-D Hydrodynamic Model under Simplified and Detailed Bathymetric Conditions. Water 2021, 13, 3076. https://doi.org/10.3390/w13213076
AMA Style
Hafeez MA, Inoue T. Determination of Flow Characteristics of Ohashi River through 3-D Hydrodynamic Model under Simplified and Detailed Bathymetric Conditions. Water. 2021; 13(21):3076. https://doi.org/10.3390/w13213076
Chicago/Turabian StyleHafeez, Muhammad Ali, and Tetsunori Inoue. 2021. "Determination of Flow Characteristics of Ohashi River through 3-D Hydrodynamic Model under Simplified and Detailed Bathymetric Conditions" Water 13, no. 21: 3076. https://doi.org/10.3390/w13213076
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