| Summary: | 碩士 === 逢甲大學 === 土木及水利工程所 === 92 === Wu-Shi River is the fourth greatest river in Taiwan. The tidal reach of Wu-Shi River has been seriously polluted. Therefore, to understand the transport characteristics of the river is an essential. Two measurements were performed to
collect the environmental hydraulic data for the tidal reach of Wu-Shi River. Then, based on the cross-section, water lever, current velocity and salinity of Shi-Bin Bridge, a salt transport analysis were applied to calculate the instant 1-D dispersion coefficient K and the tidal averaged 1-D dispersion coefficient <K>. An equation was developed for the instant 1-D dispersion coefficient K and tidal averaged 1-D
dispersion coefficient <K> in Wu-Shi River, based on 6 sets of measured dada. The background fluorescent concentration was investigated for the calculation of the tidal averaged 1-D dispersion coefficient <K>. The result shows that, K is –3 to 238 m2/s for the first measurement, and -70 to 268 m2/s for the second measurement, and the values are much influenced by tidal intensity. The <K>’s, obtained by three
salt transport methods are 286、509、193 m2/s for the first measurement and 78、-84、187 m2/s for the second, and the <K>, obtained by the tracer study is 96 m2/s . The transport characteristic is decomposed to freshwater discharge effect, tidal pumping effect, vertical shear dispersion effect, transverse shear dispersion effect and small scale effect due to wind, topography and coriolis force, so that the
dispersion at Shi- Bin Bridge may be analyzed in detail.
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