A Non-Point Source Load Simulation of the Yangtze River Basin, China

This study uses an interpolation method in spatial simulation to simulate immeasurable factors affecting the non-point source (NPS) load on the Yangtze River basin. Spatial simulation is also applied by the improved export coefficient model to present NPS loads. Self-organizing maps are used to expose the correlation of these factors to NPS load. The results show that the highest precipitation impact factor value distributes mainly in the eastern region of the basin; the lower value locates at north western of the basin. The lowest terrain impact factor located mainly at the eastern and western region; the highest terrain impact factor value distributes spread at middle region of the basin. The highest non-point source load value distributes at middle region of the basin; the lowest value distributes in the western region of the Yangtze River basin. Grassy land factor; agriculture land factor; forest land factor; precipitation factor; and fertilizer factor have correlation with population factor in the highest value. Precipitation factor and forest land factor; population factor and agriculture land factor; grassy land factor and barren factor have correlation with each other at the lowest value. Wetland factor and barren land factor; total nitrogen load factor and total phosphorus factor have closely correlation each other at the lowest and highest value. Forest cover rate factor has no correlation with others.