碩士 / 國立聯合大學 / 土木與防災工程學系碩士班 / 101 / The hydrodynamic characteristics and salt distributions in tidal rivers, estuaries, and coastal waters are critically important for the transportation of pollution between river and coastal sea. The Danshuei River is the third largest river and the largest estuarine system in Taiwan, occupying nearly half the population of Taiwan in Taipei area. Due to the population growth and industrial and commercial development in Taipei area, the serious pollutions result in poor water quality and subsequently affect the quality of environmental health and ecology.
In the present study, hydrological and geographic data were used to establish a three-dimensional hydrodynamic model. The model simulated results were calibrated and validated with measured water level, current, and salinity in 2010 and 2011. The mean absolute errors (MAE) between modeled and measured water levels are in the range of 0.09~0.34 m. The MAE values of current are 0.2 m/s and 0.13 m/s for Taipei Bridge and Kuan-Du Bridge, respectively. The MAE values of salinity are 1.22~2.71ppt at flood tide and 0.49~0.82 ppt at ebb tide. The results show that model simulations are in agreement with measured data. The water quality model was then incorporated into the hydrodynamic model and validated with measured data of water quality in the Danshuei River estuarine system. The MAE values of water quality state variables were 0.38~2.17 mg/L, 0.05~6.56 mg/L, 0.15~0.52 mg/L, and 0.01~0.19 mg/L for DO, CBOD, NH4, and TP, respectively. The results also indicate that model simulations are in agreement with measured water quality data.
The validated water quality model was applied to investigate the impacts of pollution loads reduction in the estuary on water quality conditions under the low flow condition. The results showed that the DO concentration has improved significantly in the Danshuei River-Tahan Stream due to the reduction of pollution loadings. The maximum DO concentration increases by 2.3 mg/L, 1.5 mg/L, and 0.98 mg/L, respectively, in the Danshuei River-Tahan Stream, the Hsintien Stream, and the Keelung River, respectively. The DO concentration is higher than 2mg/L for all rivers. According to the model simulation, water quality in the estuarine system will be significantly improved after the pollutant load reduction.
| Identifer | oai:union.ndltd.org:TW/101NUUM0653003 |
| Date | January 2013 |
| Creators | CHAN, WEN-TING, 詹文婷 |
| Contributors | Liu, Wen-Cheng, 柳文成 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 142 |
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