| Danjiangkou Reservoir is the source of South-North Water Transfer Project, the country's largest drinking water source protection areas of extremely high quality requirements, while ensuring that the river water flow to the north, the South-North Water Transfer Project is the key to success. Danjiangkou Reservoir for weeks and the catchment area of serious non-point source pollution. As a result, research of Danjiangkou reservoir area non-point source pollution to the protection of the Danjiangkou Reservoir has a very important significance. Hu Jiashan watershed is tributary from north to south into Danjiangkou reservoir area.with hills, land-based gang and a small amount of low-Hill, Hu Jiashan watershed has a representative in Danjiangkou reservoir. In this paper, Hu Jiashan small watershed for the study, to choose representatives of the different types of land-use run-off area. At the same time, set up 28 sampling points and make real-time monitoring in different types of land-use surface. The combination of small watershed land-use conditions, rainfall monitoring data and Universal Soil Loss Equation (USLE), look at the whole basin of the loss of non-point source pollution laws.The study found that the Danjiangkou reservoir area Hu Jiashan small watershed nitrogen, phosphorus concentrations showed significant differences in time and space, coefficient of non-point source pollution variation have no obvious law in different hydrological period, The main form of nitrogen, phosphorusin water is not the same, in the process of relocation of the concentration of nitrogen and phosphorus are also obvious. Hu Jiashan small watershed three or four month period, opposite the source of fertilizer pollution than the impact of rainfall throughout the year accounted for 86% of the month 7, 8, the runoff at the same time, the patterns of pollutants, land-use types, opposite the source of pollutants Loss obviously different.According to theoretical calculations, the use of the Universal Soil Loss Equation (USLE) and SCS rainfall runoff model for small watershed of the non-point source pollution load estimates for the entire small watershed nitrogen absorption of the total for the loss of 2.29t, Various types of land-use ratio of the amount of the loss of dry land were 51.95%, 41.48% of grassland and woodland 6.55 percent, 0.02 percent villages, adsorption-P for the total loss of 1.2lt, of which 63.15 percent dry land, grassland 31.58 percent, 5.26 percent woodland, villages 0.01%. Surface runoff of nitrogen and phosphorus dissolved in the total loss is 35.79t and 6.01t, which dissolved nitrogen in the total loss to the highest village, has reached 76.06 percent. This was followed by dry land and forest land, the loss of dissolved phosphorus to the total villages, up to dry land, 76.49 percent and 16.57 percent respectively, followed by woodland, grassland at least. From the adsorbed and dissolved nitrogen and phosphorus relations, Hu Jiashan small watershed into the Danjiangkou Reservoir in nitrogen and phosphorus nutrient absorption by the main state. |
