The Application Of Model Parameter Sensitivity Analysis To Water Pollution Control In The Songhua River In The Dry Season

River pollution is one of the most prominent problems in the widespread global environmental problems. Changbaishan Tianchi originated in the Second Songhua River, carrying the heavy responsibility of Heilongjiang and Jilin provinces in most areas of about 60 million population production and living water. In recent years, with the continuous development of coastal industries, urban sewage discharge, as well as a large number of rural non-point source pollution continues to expand, the water quality problem has never been a good solution. It not only affects people's daily life and economic development, but also aggravates the water shortage crisis. Therefore, the majority of urban residents are generally concerned about the issue of the Songhua River Basin governance and management of surface water environment.In this paper, parameters of river water quality model study of the sensitivity of the issue as a starting point, through the analysis of the Songhua River in Harbin natural geographical conditions, characteristics of water resources, pollution, as well as pollutants migration and transformation laws, the final decision to choice of two-dimensional steady-state mixed-decay mode parameters for the study of the sensitivity analysis in the Environmental Impact Assessment Technical Guideline - Surface Water Environment (HJ/T2.3-93). It is not only enhancing the theoretical understanding of rivers, but also for river pollution control and environmental management decision-making theory.In order to analysis and clarify parameter sensitivity of the issue from different perspective, the paper combines the traditional sensitivity analysis and regression analysis of modern, at the same time through the use of Environmental Impact Assessment Assistant Special for Ground Water software, based on the a large number of spreadsheet, comprehensive and systematic understanding of the sensitivity of various parameters of the model. We can conclude that: discharge of sewage (Q_p) = sewage discharge concentration (C_p) > background concentration of river (C_h) > current velocity (u) > horizontal diffusion coefficient (M_y) > degradation coefficient (K₁). Discharge of sewage (Q_p), sewage discharge concentration (C_p) and background concentration of river (Ch) have completely positive relation with the pollutant concentration of predicted section and degradation coefficient (K₁) has completely negative relation with the pollutant concentration of predicted section. Both current velocity (u) and horizontal diffusion coefficient (M_y) are meeting the power function equation and there is a negative correlation to the full and so on. In order to completely eradicate the problem of Songhua River in Harbin, the key is from pollution source, which is restrictions on the quantity of sewage discharged and reduce the concentration of sewage. Especially in the dry season, due to temperature, precipitation and other factors, current velocity, horizontal diffusion coefficient and degradation coefficient would reduce. If not effectively control pollution sources, pollution is bound to increase.At last, the paper makes a comparison between measured values and simulation values of Wenchang wastewater treatment plant downstream 500m, 800m and 1 000m, the average relative error of them is only 9.47%. It explains that the Two-dimensional steady-state mixed-decay mode can be well used to simulate and predict the behavior of pollutants in the water environment, makes the simulation results closer to measured values.