A basin-scale pollutant load and its transportation processes are discussed in this study. The unit loading method combined with census and GIS data is used to estimate spatial distribution of pollutant load within the basin. the method allows grid-base representation of pollutant load, and makes it possible to link the pollutant production with distributed hydrological model. The spatial distribution of pollutant load and channel purification process model are then integrated into the distributed hydrological model to simulate dynamic behavior of water quality and quantity along the stream. These methods have potential to be used for understanding the water quality over the large area with less data requirement, and could be applied for integrated river basin management.
