博士 / 國立臺灣大學 / 農業工程學研究所 / 87 / The estuary, together with the tidal freshwater river upstream of it, is the pathway for exchange of water and materials between its drainage basin and coastal ocean. To predict the fate and transport of materials from land to ocean, it is essential to understand the hydrodynamic characteristics of this stretch of the river. This study investigates the major components of water movement in the estuarine system : tidal flow, freshwater river flow and estuarine (or residual) circulation. The longitudinal and vertical salinity distributions are also investigated as a forcing function of, as well as a response to, the estuarine circulation.
The purposes of this study are to develop a vertical two-dimensional numerical model which includes the capability to model tributaries and to study the hydrodynamic and water quality characteristics of estuarine system. The hydrodynamic model is based on the principles of conservation of volume, momentum and mass, and the water quality model on the conservation of mass alone. The flow conditions at the confluences of mainstem and tributaries are solved by expanded continuity, momentum and mass-balance equations.
After model development, the numerical model is applied to investigate the Tanshui River system, the largest estuarine system in Taiwan with drainage basin including the capital city of Taipei. It consists of three major tributaries : the Tahan Stream, Hsintien Stream and Keelung River. The study investigates the hydrodynamic characteristics of the tidal reaches of the river system by means of theoretical analysis and numerical simulation. The model is calibrated and verified with observational field data. The calibrated and verified parameters include Manning* friction coefficient, the coefficients in turbulence diffusion terms and the coefficients of eight-water quality state variables.
As examples of model utilities, the calibrated and verified model is used to investigate the tidal flow and salinity conditions in the Tanshui estuarine system and its estuarine wetland under the conditions with and without Kuan-Du dike. The model is also used to compute the salinity distributions and to predict future water quality conditions under several scenarios of wastewater diversion and under various hydrological conditions. The results show that the model has potential for more general diagnostic applications and prediction of pollutant transport and fate. It also can be used as an aid for making waste load allocations, management decisions and environmental impact analyses.
| Identifer | oai:union.ndltd.org:TW/087NTU00404001 |
| Date | January 1998 |
| Creators | Liu, Wen-Cheng, 柳文成 |
| Contributors | Hsu, Ming-Hsi, 許銘熙 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 272 |
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