Author(s): Hiroshi Nagashima; Nozomu Yoneyama
Linked Author(s): Nozomu Yoneyama
Keywords: Tsunami; Salinity; 3D numerical analysis; Estuary barrage; Water purification
Abstract: In the event of a tsunami, salt water flows into rivers and water purification plants are forced to stop taking water from the rivers in order to prevent high level of salinity from entering into the plant because salt causes a breakdown of the machinery. This leads to interruption of water supply in the time of a disaster. In this study, the authors developed a salinity transport simulation model that can carry out a three-dimensional salinity behavior analysis in specific area and a horizontal two-dimensional tsunami propagation analysis in the ocean at the same time for the purpose of predicting the salt water behavior in rivers at the time of a tsunami so that the influence of the boundary of the 3D domain would be excluded without greatly increasing the calculation load. This model was applied to the salt water behavior analysis during a tsunami attack in the tidal area of the Yodo River in Osaka, western Japan, where they have an estuary barrage and a few intakes at a small distance upstream. Then the spatial distribution and temporal change of salt water under various river flows were quantitatively predicted and it was possible to evaluate the salinity influence on taking water. Furthermore, the authors examined countermeasures to diminish the duration of stopping taking water and got an effective countermeasure.
Year: 2018