『Abstract
　Jialing River, which covers a basin area of 160,000 km² and a length of 1,280 km, is the largest tributary of the catchment area in Three Gorges Reservoir Area, China. In recent years, water quality in the reservoir area section of Jialing River has been degraded due to land use and the rural residential area induced by non-point source pollution. Therefore, the semi-distributed land-use runoff processes (SLURP) hydrological model has been introduced and used to simulate the integrated hydrological cycle of the Jialing River Watershed (JRW). A coupling watershed model between the SLURP hydrological model and dissolved non-point source pollution model has been proposed in an attempt to evaluate the potential dissolved non-point source pollution load; it enhances the simulation precision of runoff and pollution load which are both based on the same division of land use types in the watershed. The proposed model has been applied in JRW to simulate the temporal and spatial distribution of the dissolved total nitrogen (DTN) and dissolved total phosphorus (DTP) pollution load for the period 1990-2007. It is shown that both the temporal and spatial distribution of DTN and DTP load are positively correlated to annual rainfall height. Land use is the key factor controlling the distribution of DTN and DTP load. The source compositions of DTN and DTP are different, where average DTN pollution load in descending order is land use 67.2%, livestock and poultry breeding 30.5%, and rural settlements 2.2%; and for DTP, livestock and poultry breeding is 50%, land use 48.8%, and rural settlements 1.2%. The contribution rates of DTN and DTP load in each sub-basin indicate the sensitivity of the results to the temporal and spatial distribution of different pollution sources. These data were of great significance for the prediction and estimation of the future changing trends of dissolved non-point source pollution load carried by rainfall runoff in the JRW and for studies of their transport and influence in the Three Gorges Reservoir.

Keywords: SLURP hydrological model; Jialing River Watershed; Non-point source pollution; Dissolved nitrogen and phosphorus; Spatial and temporal distributing simulation』

Introduction
　Study area
Materials and methods
　Basic data sources
　SLURP hydrological model
　　Principle of the SLURP model
　　Validation of parameters optimization and simulation
　Dissolved pollution load model of different land use types
　　DTN and DTP pollution model of different land use
　　The determination of the DTN and DTP runoff concentration
　　　Monitoring and analytical methods
　　　The determination of DTN and DTP concentration
　　The determination of transport loss coefficient
　　DTN and DTP load model of rural settlements
　　The determination of the sewage (excretion) coefficient and producing pollution coefficient
Results and discussion
　The annual variability of DTN and DTP pollution load
　The sources composition of DTN and DTP pollution load
　The spatial distribution DTN and DTP pollution load
　The contribution rates of DTN and DTP load in each sub-basin
　Simulation results verification
Conclusions
Acknowledgments
References