Abstract Water-born sediments can be transported from land to the ocean. Subsequently, waves and currents influence the sediments in their transport processes and distribution, leading to the change of the nearshore morphology and bedforms. The purpose of this study is to analyze the coastal sediments transport patterns in southern Taiwan. Two major approaches are used in this study. One is a statistical method called McLaren Model and it¡¦s derivative Transport Vector, and another is in situ process-response observation. McLaren Model uses three granulo-metric parameters to analyze net sediment transport vectors in coastal area near the Tsengwen River mouth and Kaohsiung Harbor. Transport Vectors represent the time-averaged trends. The another method is to make in situ observation on the Kaoping continental shelf. Between December 12 and December 28, 2004, an instrumented tetrapod was deployed with an upward-looking ADCP and two LISST-100s. Another downward-looking ADCP was mounted at 2 m above bed (mab). Water samples were pumped at 1 and 0.5 mab hourly on December 13, December 20 and December 27 for suspended sediment concentration (SSC) analysis. The echo intensity (EI) can reflect the SSC. The volume concentration of thirty-two grain sizes were observed by LISST-100, so we can transform the volume concentration to suspended sediment concentration by linear correlation equation. The residual sediment transport patterns for the north of Tsengwen River are directed towards the north-west along the coastline, and the sediments around the Tsengwen River mouth are transported offshore in a radial pattern. The transport directions of sediments north of Kaohsiung Harbor are also directed towards the northwest along the coastline and southeastwards south of the harbor. The observed SSC fluctuations on Kaoping continental shelf are dominated by waves and currents. The cross-correlation of EI with current shear velocity is better than with other shear velocities. The results indicate that the SSC fluctuations are dominated by currents. In this area, the net sediment transport is northwestward, in which the amount of grain-size of 63-250£gm (very fine sand and fine sand) is the greatest. This indicates that very fine-grained and fine-grained sediments are more easily transported by currents.

In order to better understand the flow dynamics of the Kaoping Submarine Canyon (KSC), this study conducted a series of field experiments to monitor the current, temperature, salinity and tide near the KSC by using shipboard ADCP, CTD and moorings of RCM-8 and workhorse ADCP. Three cruises of Sb-ADCP and CTD have been carried out in September and December of 1999 and May 2000, each lasting two days, while mooring experiment was conducted in June and July, 2000. Least-square fit was applied to the time series Sb-ADCP data of each grid to derive the amplitude and phase of M2 tidal current and the residual flow in the KSC. Our results revealed that a string baroclinic flow field was present in the KSC. Tidal ellipse of the bottom current is dominated by M2 component, with higher M2 percentage in deeper layers. The major axis of the tidal ellipse is parallel to the direction of the canyon axis. In floods, the bottom layer flows down-canyon and the surface layer flows southeastward along the coastline. In ebbs, the situation is reversed. Variations of the temperature and salinity in the bottom layer also exhibit periodic oscillation of the M2 frequency. Daily temperature fluctuation in summer can reach 8 oC, indicating the existence of internal tide in the KSC. The surface residual current flows toward the south east in September and May, with a maximum speed of approximately 30 and 50 cm/s, respectively; the result is probably due to the bifurcation of the summer monsoon flows by the southwestern coastline of Taiwan. In December the surface residual current is northwestward, the maximum speed can reach 80 cm/s. Such a northward mean flow is probably originated from branching of the Kuroshio through Bashi Channel in the winter monsoon season. To summarize, mechanisms for the upwelling event in the KSC consist of surface flow direction, tidal range, and the stratification. The upwelling event occurs more often in the KSC between May and September with the surface mean current flows southeastward or left-bounded. In December when the surface mean current flows northwestward or right-bounded, the upwelling event is rare. An eddy structure of 7 ~ 9 km length scale was observed north of Liu-Chiu Yu, a result possibly produced by Karman vortex street for strong geophysical flows behind an island.

In order to better understand the flow dynamics of the Kaoping Submarine Canyon (KSC), this study conducted a series of field experiments to monitor the current, temperature, salinity and tide near the KSC by using shipboard ADCP, CTD and moorings of RCM-8 and workhorse ADCP. Three cruises of Sb-ADCP and CTD have been carried out in September and December of 1999 and May 2000, each lasting two days, while mooring experiment was conducted in June and July, 2000. Least-square fit was applied to the time series Sb-ADCP data of each grid to derive the amplitude and phase of M2 tidal current and the residual flow in the KSC. Our results revealed that a string baroclinic flow field was present in the KSC. Tidal ellipse of the bottom current is dominated by M2 component, with higher M2 percentage in deeper layers. The major axis of the tidal ellipse is parallel to the direction of the canyon axis. In floods, the bottom layer flows down-canyon and the surface layer flows southeastward along the coastline. In ebbs, the situation is reversed. Variations of the temperature and salinity in the bottom layer also exhibit periodic oscillation of the M2 frequency. Daily temperature fluctuation in summer can reach 8 oC, indicating the existence of internal tide in the KSC. The surface residual current flows toward the south east in September and May, with a maximum speed of approximately 30 and 50 cm/s, respectively; the result is probably due to the bifurcation of the summer monsoon flows by the southwestern coastline of Taiwan. In December the surface residual current is northwestward, the maximum speed can reach 80 cm/s. Such a northward mean flow is probably originated from branching of the Kuroshio through Bashi Channel in the winter monsoon season. To summarize, mechanisms for the upwelling event in the KSC consist of surface flow direction, tidal range, and the stratification. The upwelling event occurs more often in the KSC between May and September with the surface mean current flows southeastward or left-bounded. In December when the surface mean current flows northwestward or right-bounded, the upwelling event is rare. An eddy structure of 7 ~ 9 km length scale was observed north of Liu-Chiu Yu, a result possibly produced by Karman vortex street for strong geophysical flows behind an island.

Constructed wetlands had been used for water treatment worldwide. The efficiency of wastewater treatment in a constructed wetland depends on its design, types of aquatic plants and microbial community present in this wetland. The goal of this study is to analyze the microbial populations in KaoPing River Rail Bridge constructed wetland which was designed to remove the polluted material from municipal sewage and industrial wastewater. Sediment and water samples were collected every 3 months from April, 2007 to April, 2008. The bacterial community diversities were analyzed by PCR-DGGE of the bacterial 16S rRNA gene. Results show approximately 60% BOD, 41% COD, 46% nitrate, 22% total nitrogen, and 97% coliforms were removed by this wetland system. DGGE profiles revealed the bacterial community diversities shifted progressively from the entry to the exit of both A and B systems in this wetland. The microbial populations in water, sediment, biofilms on plants, and soil were quite different from each others. The fecal indicator Escherichia coli was used as a marker to monitor the fecal contamination in all samples. From PCR-DGGE profiles, E. coli could be successfully removed by this wetland system. In conclusion, this constructed wetland is a very successful system for wastewater treatment and is able to remove most of the pollutants before they are discharged into KaoPing River. The results of this study provided useful suggestions for the government to assess the bacterial diversities and the efficiency of this wetland system, to protect people from hazardous risks, and to manage a constructed wetland in the future.