The Effect Of Transformation Of Land Utility On Non-point Pollution Source In Drinking Water Source Area

While our country's economy has been developing rapidly in recent years, the condition of drinking water security, which is vital to the everyday life quality of people, is an important issue to be worried. At present time, drinking water as one of the most important water resources has many problems in the areas of water quality, water volume and resource management, etc. The security of people's drinking water has been threatened seriously. Since point source pollution of the drinking water source has been under the active control, the nonpoint source pollution becomes an important factor of threat to the drinking water security.This article analyzes the land utilization change of Dongpu Reservoir in the recent ten years (1996-2005 years), uses phosphorus flux coefficient model such as the Johnes model and Soranno to estimate the region's TN and TP pollution load. Based on the computation in Dongpu Reservoir TN and TP environmental capacity, this article proposes a linear optimization to the land utilization using linear programming's method. The main conclusions of this article are listed as follows:(1) Crop production lands' TN and TP nonpoint source pollution occupies 50% of the total pollutions. The farmland surface runoff is important origin of the nonpoint source pollution in Dongpu Reservoir.(2) During the ten years from 1996 to 2005, the acreage change rate of crop production land in Dongpu Reservoir area is smaller than 21%, but the unit area's nitrogenous fertilizer and phosphate fertilizer employment quantity of the highest year, compared to the lowest year, increased 2.9 times, 7.89 times separately. In these ten years, the load change rate of crop production lands' nonpoint source pollution was corresponding to annual average employment quantity change rate of nitrogenous fertilizer and phosphate fertilizer.(3) In these ten years, the TN and TP nonpoint source pollution load of city land kept a growing tendency, and grew 1.96 times from 1996 to 2005.(4) According to phosphorus flux coefficient model such as the Johnes model and Soranno, the TN and the TP nonpoint source pollution load in Dongpu Reservoir area in the year of 2005 are 257.07t/a, 14.89t/a respectively. The monitor data confirms that the TN estimate is accurate, while the TP estimate error slightly larger.(5) The income is 687,720,000 RMB in land utilization most superior year after linear optimization, the TN pollution load is the 80.6t/a, TP pollution load is 6.24 t/a.(6) The corresponding measure to control and prevent the water pollution, based to the characteristic of Dongpu Reservoir's nonpoint source pollution, are proposed: effective controls of the change of land utilization nature; accurate balanced applies fertilizer; processing of countryside solid waste into useful resources; artificial wetland purification system; adjusting of the agricultural production structure; physical protection project; suitable pisciculture; unifies with the prevention of air pollution; and so on.