碩士 / 國立中央大學 / 水文所 / 93 / The estuary is the primary conduit for the transport of water and material from its drainage basin to the coastal ocean. The ultimate fates of land-derived materials, such as pollutants, depend on the water movement in the estuaries. To predict the fate and transport of materials from land to the ocean requires the knowledge of water movement through this stretch of water body. The Danshuei River system is the largest estuarine system in Taiwan. It consists of three major tributaries: Tahan Stream, Hsintien Stream and Keelung River. In addition to the barotropic flows forced by the tide and river discharges, the baroclinic flow forced by seawater intrusion is another important transport mechanism in the Danshuei River estuarine system.
In this study, a three-dimensional hydrodynamic model (UnTRIM-3D) was used to simulate tidal current and salinity distributions in the Danshuei River estuarine system and adjacent coastal sea. The unstructured orthogonal grid in this model is adopted to fit complicated boundaries. It is flexible to permit local mesh refinements in areas of interest only and to reduce computational time.
The upstream boundaries of the computation domain are: Cheng-Ling Bridge (Tahan Stream), Hsiu-Lang Bridge (Hsintien Stream), Jiang-Bei Bridge (Keelung River) and downstream boundary is at the coastal sea. First, a single constituent tidal was used as forcing function at the coastal sea boundary for preliminary model calibration of the value of Chezy friction coefficients. The use of a single constituent tide expedites the extraction of tidal ranges from model outputs for comparison with prototype data. Five-constituent tidal was then used for fine-tune calibration by matching the observed amplitudes and phases of the five tidal constituents. Using the field data in 2000 for model verification, the model was run to simulate the prototype condition. The comparisons between model results and field data of tidal elevation, current velocity, salinity, and residual current indicate that the model is accurate and suitable for the Danshuei River estuarine system.
After the model calibration and verification, the 3D model was applied to investigate the residual circulation and salinity distributions under mean and low ( ) flow conditions. The model was also used to evaluate the effects on residual current and salinity distributions in the Keelung River due to the channel regulation of Keelung River.
Key words: Estuary and coastal sea; UnTRIM-3D model; hydrodynamic; salinity; calibration and verification; model application; channel regulation.
| Identifer | oai:union.ndltd.org:TW/093NCU05761003 |
| Date | January 2005 |
| Creators | Win-Po Chen, 陳偉柏 |
| Contributors | Wu-Ting Tsai, 蔡武廷 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 83 |
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