Response of Salt Transport and Residence Time to Geomorphologic Changes in an Estuarine System
Anthropogenic changes in tidal estuaries have significantly altered bathymetry and topography over the past half century. The geomorphic-driven changes in estuarine hydrodynamics and salt transport remain unclear. To explore this issue, a SELFE (Semi-implicit Eulaerian-Lagrangian Finite Element) -ba...
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| Format: | Article |
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MDPI AG
2020-04-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/12/4/1091 |
| _version_ | 1797570858513858560 |
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| author | Wen-Cheng Liu Min-Hsin Ke Hong-Ming Liu |
| author_facet | Wen-Cheng Liu Min-Hsin Ke Hong-Ming Liu |
| author_sort | Wen-Cheng Liu |
| collection | DOAJ |
| description | Anthropogenic changes in tidal estuaries have significantly altered bathymetry and topography over the past half century. The geomorphic-driven changes in estuarine hydrodynamics and salt transport remain unclear. To explore this issue, a SELFE (Semi-implicit Eulaerian-Lagrangian Finite Element) -based model was developed and utilized in a case study in the Danshui River, Taiwan. The model was calibrated and validated using observed water level, current, and salinity data from 2015, 2016, and 2017. The performance of the SELFE model corresponded well to the measured data. Furthermore, the validated model was utilized to analyze the hydrodynamics, residual current, limit of salt intrusion, and residence time under the predevelopment (1981) and present (2015) conditions. The predicted results revealed that the time lag of water surface elevation at both high tide and low tide under the present condition was approximately 0.5–2 h shorter under the predevelopment condition. The residual circulation under the predevelopment condition was stronger than under the present condition for low flow, causing the limit of salt intrusion to extend further upstream under the predevelopment condition compared to the limit of salt intrusion under the present condition. The calculated residence time under the predevelopment condition was longer than the residence time under the present condition. The freshwater discharge input is a dominating factor affecting the salt intrusion and residence time in a tidal estuary. A regression correlation between the maximum distance of salt intrusion and freshwater discharge and a correlation between residence time and freshwater discharge were established to predict the limit of salt intrusion and residence time under the predevelopment and present conditions with different scenarios of freshwater discharge input. |
| first_indexed | 2024-03-10T20:31:25Z |
| format | Article |
| id | doaj.art-d72c3c6870f5419ea5b5962e1c109464 |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-10T20:31:25Z |
| publishDate | 2020-04-01 |
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| series | Water |
| spelling | doaj.art-d72c3c6870f5419ea5b5962e1c1094642023-11-19T21:23:39ZengMDPI AGWater2073-44412020-04-01124109110.3390/w12041091Response of Salt Transport and Residence Time to Geomorphologic Changes in an Estuarine SystemWen-Cheng Liu0Min-Hsin Ke1Hong-Ming Liu2Department of Civil and Disaster Prevention Engineering, National United University, Miaoli 36063, TaiwanDepartment of Civil and Disaster Prevention Engineering, National United University, Miaoli 36063, TaiwanDepartment of Civil and Disaster Prevention Engineering, National United University, Miaoli 36063, TaiwanAnthropogenic changes in tidal estuaries have significantly altered bathymetry and topography over the past half century. The geomorphic-driven changes in estuarine hydrodynamics and salt transport remain unclear. To explore this issue, a SELFE (Semi-implicit Eulaerian-Lagrangian Finite Element) -based model was developed and utilized in a case study in the Danshui River, Taiwan. The model was calibrated and validated using observed water level, current, and salinity data from 2015, 2016, and 2017. The performance of the SELFE model corresponded well to the measured data. Furthermore, the validated model was utilized to analyze the hydrodynamics, residual current, limit of salt intrusion, and residence time under the predevelopment (1981) and present (2015) conditions. The predicted results revealed that the time lag of water surface elevation at both high tide and low tide under the present condition was approximately 0.5–2 h shorter under the predevelopment condition. The residual circulation under the predevelopment condition was stronger than under the present condition for low flow, causing the limit of salt intrusion to extend further upstream under the predevelopment condition compared to the limit of salt intrusion under the present condition. The calculated residence time under the predevelopment condition was longer than the residence time under the present condition. The freshwater discharge input is a dominating factor affecting the salt intrusion and residence time in a tidal estuary. A regression correlation between the maximum distance of salt intrusion and freshwater discharge and a correlation between residence time and freshwater discharge were established to predict the limit of salt intrusion and residence time under the predevelopment and present conditions with different scenarios of freshwater discharge input.https://www.mdpi.com/2073-4441/12/4/1091hydrodynamicssalt water intrusionresidence timethree-dimensional modelgeomorphologic changeestuarine system |
| spellingShingle | Wen-Cheng Liu Min-Hsin Ke Hong-Ming Liu Response of Salt Transport and Residence Time to Geomorphologic Changes in an Estuarine System Water hydrodynamics salt water intrusion residence time three-dimensional model geomorphologic change estuarine system |
| title | Response of Salt Transport and Residence Time to Geomorphologic Changes in an Estuarine System |
| title_full | Response of Salt Transport and Residence Time to Geomorphologic Changes in an Estuarine System |
| title_fullStr | Response of Salt Transport and Residence Time to Geomorphologic Changes in an Estuarine System |
| title_full_unstemmed | Response of Salt Transport and Residence Time to Geomorphologic Changes in an Estuarine System |
| title_short | Response of Salt Transport and Residence Time to Geomorphologic Changes in an Estuarine System |
| title_sort | response of salt transport and residence time to geomorphologic changes in an estuarine system |
| topic | hydrodynamics salt water intrusion residence time three-dimensional model geomorphologic change estuarine system |
| url | https://www.mdpi.com/2073-4441/12/4/1091 |
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