||Kaohsiung Harbor was a narrow coastal lagoon. It has become the most important harbor in Taiwan, even internationally important, through a century development since the Japanese colonial period. The water quality of the harbor and the Love River became worse and worse due to intensive industrial developments since 1970. The sewerage system of Kaohsiung was not properly constructed before 1990, which cause the water seriously polluted. Since 1990, Kaohsiung city government started the interceptor project to improve the water quality of the Love River and the harbor. However, there are clear seasonal patterns in the south of Taiwan, which divides the year into dry and wet season. The dry weather flows are intercepted into sewer mains and convey to treatment which improves the water quality condition during the dry season. However, sediments accumulated in the drainage systems were flushing out to the Love River during the wet season because the interceptor had to open letting rain storm discharge into the River, particularly during typhoon periods. In order to study the seasonal variation of the water from Love River to Kaohsiung Harbor and the neighboring coastal seas, a 3-D hydrodynamic model (SELFE) coupled with an ecological model have been constructed. Decades of water quality data have been collected and analyzed as basic information for the study. Besides the hydrodynamics and the nitrogen cycle in the water environment are modeled, silicate and phosphate are considered as sufficiently supplied.|
According to the model results, no matter in dry or wet season, ammonia, nitrate and COD in the Love River were lower, oxygen and zooplankton were higher after the completion of the interceptor project. Though phytoplankton and ammonia were still a little higher in the harbor the water quality of the Kaohsiung Harbor and its associated waters was much improved. The interceptors were opened during typhoon periods, loads of nutrients accompanied with fresh water flushed into the Love River. Model results are shown little difference during storm season before and after the interceptor project because the gates were all opened. It is also means the nutrients can affect Kaohsiung Harbor and to the coastal water too. The nutrients can be transported into coastal water in about 96 hours. The algal bloom can be observed from the model results 2 days after typhoon left.