| The nonpoint sources (NPS) pollution, which is also called diffuse sources of pollution,occurs as widespread precipitation and run-off move over and through the ground or by other ways, picking up pollutants as they go. With the continuous development of controlling point sources pollution, nonpoint sources pollution has increased significantly over the past few years, and the voice to restrain NPS is gradually stronger. The nonpoint sources pollution has become the main pollution source of the surface water. By comparison with the point sources pollution, the nonpoint sources pollution is related to the larger space-time and more uncertainties, and pollution process more complicated, and pollution more seriously; all the reasons above increase the difficulty of researching and managing the nonpoint sources pollution.The industrial effluents and the municipal sewages of Jilin province have been disposed in large scale, and the quality of the surface water has been improved greatly. As we know, the surface water is the main water supply of manufacture and living in Jilin province. However, according to the assessment to the monitor dates of all the section of 2005, only the 38.46% is up to the standard. Thus, water shortage is limiting the economic development of Jilin province.With the implement of the policy of the revitalization of the old industrial base of northeast in China, the pace of the industrialization and the urbanization has noticeably quickened in Jilin province. Meanwhile, other policies and projects which benefit people, which result in non-point pollution, are degrading directly and indirectly the quality of the surface water of Jinlin province. Therefore, it is imperative to develop the research on non-point pollution of the surface water in Jinlin province.The current status of surface water nonpoint sources pollution at home and abroad are described in this paper, including NPS process simulation and model components and existing management practices. The shortage of existing models and methods is presented, that is, the calculated results are lager than the actual quantity to the surface water. The types of NPS pollution and their effects to the surface water are discussed. According to the sources, the nonpoint sources of pollution is divided into the followings ,agricultural runoff (from farm animals and croplands), storm-water drainage (streets, parking lots, and lawns), atmospheric deposition (from air pollutants washed to earth or deposited as dry particles), aquatic cultural, etc.This study is carried out on the basis of the monitor dates of the four major water systems, fifteen rivers and sixty-four sections. The ratio of ammonia-nitrogen (NH3-N) pollutant of eleven rivers is increasing, by means of the quality evaluation and the pollution trend analysis on the surface water environment in the past five years, so NH3-N is taken as the research object to make a case study.First, the NH3-N decaying coefficients were derived from by the two-point method, from 0.001 to 0.6 per day, of which in high flows season from 0.05 to 0.6 per day, in low flows season from 0.001 to 0.3, and in even flows season from 0.003 to 0.5. The minimum was in the kaoshannanlou section, in which the water was polluted seriously, and the maximum was shaokou section, where the water quality was better. Second, the NPS pollution loading model was developed on the basis of S-P model and the pollutants decaying-mixture rule, including river, point sources and nonpoint sources quantity. The case study showed the NH3-N pollution loading was 107238.46 ton per year in Jilin province, of which Songhua River water systems 73124.36t/a,Liao River systems 30632.46t/a,Yalv River systems 2030.98t/a,Tumen River systems 1450.66t/a. The nonpoint sources NH3-N pollution loading was 3.18 times larger than point sources pollution, 33710 ton per year.The calculation results were credible and the quoted data came from a reliable source by analyzing the mid-error of statistics. The results of Yalv River (the maximum is±0.081) were the most accurate; Dongliao River (±0.551~±18.750) and Tiaozi River (±3.625~±11.709) were a little accurate because the water quality fluctuated widely; Yitong River (±0.071~±6.92), Yinma River (±1.497~±7.628) and Mudan River (±0.014~±4.129) were average; other rivers were more accurate.Finally, according to the sources, the prevent measures and suggests were provided to control the surface water NH3-N pollution, including environment management and engineering technology.In sum, the model not only simplifies the process of nonpoint sources pollution loadings calculation, but also integrates point and nonpoint sources into optimum management of surface water. So, it will be a simple and effective method to calculate the nonpoint sources pollution loadings of the surface water, due to the more actual results.
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