Application of multimedia model for the development of watershed management strategies: A case study

In most of the watersheds in Taiwan, non-point source (NPS) pollution is one of the major causes of the deterioration of surface water quality. The Kaoping River Basin, located in southern Taiwan, flows through approximately 171-km and drains towards the South Taiwan Strait. It is the largest and the most intensively used river basin in Taiwan. In the Kaoping River Basin, most of the upper catchment is used for agricultural activities including cropland and livestock farming. Field investigation results indicate that NPS pollutants contribute more than 10% of the overall pollution load to the Kaoping River. Concern about the deteriorating condition of the river water quality led the Government of Taiwan to amend the relevance legislations and strengthen the enforcement of the discharge regulations to effectively manage the river and control the NPS pollution. In this study, an integrated watershed management model (IWMM) was applied to investigate potential NPS pollution management plans in the Kaoping River watershed. Based on the results from the field investigation and model simulation, the following remedial strategies have been taken to reduce the impacts of NPS pollution on the water quality of Kaoping River: application of best management practice for NPS pollutant control; application of natural treatment systems for stormwater runoff treatment; and construction of the watershed geographical information system (GIS) and real time water quality monitoring system to effectively manage the watershed. Linking land utilization information with the NPS pollution simulation model may further provide essential information of pollution potential of NPS pollution for all sub-regions in the river basin. Experience obtained from this study will be helpful in designing the watershed management and pollution control strategies for other similar river basins.