| With the rapid socioeconomic development and the accelerating process of urbanization, the potential hazards caused by urban non-point source pollution in Songhua River basin have been gradually highlighted. Harbin city is the largest city with comprehensive functions in Songhua River basin. With the continuous processes of urbanization, the pollution of rainfall runoff non-point source pollution is becoming more and more serious, which has a serious impact on the water quality of Songhua River. In order to deeply study the impacts of strom water runoff on the water environment of Songhua River, this study monitored the quantity and quality of the storm runoff by analyzing the various pollution statuses in different functional areas in the study area. Using the storm water management model of runoff, dynamic simulation and prediction of the runoff pollution are made, which could provide theoretical basis for the research and control of non-point source pollution of urban rainfall.Taking Harbin municipal districts Majiagou Basinas an example, this study constructs a urban rainfall runoff model of point source pollution, in order to achieve the Songhua river water point source pollution control, and support the work of water environmental planning, control, management and decision-making by providing data.This study focuses on the followings:(1) within the scope of the study area selected residential areas, cultural areas, medical, gas stations, parks, five kinds of representative areas must be monitored and also set up a different sampling points are more than the rainfall runoff monitoring. Typical of the sampling points pollutants(COD, NH3-N, TP, TN) of each rainfall water quality characteristics are analyzed.(2) Construction of Harbin municipal districts Majiagou watershed non-point source pollution load model and the measured quantity, water quality data model validation. Selecting COD, TP, TN as major pollutants and using 6--8 month(2015year) three measured rainfall data model validation, as well as the total amount of pollutants in runoff simulated peak error of less than 20%. The model described in this study area has better applicability and certain reliability.(3) The pollution load simulation and accounting of the study area. In the study, storm intensity formula of Harbin in different rainfall recurrence interval(P = 0.5, P = 1, P = 2, P = 3, P = 5) for 2 hours under design context as the model’s rainfall input. For different rainfall intensities, different cities functional areas of surface conditions, scenario simulation, and analysis of the study area within the range of storm water runoff pollution, the dynamic changes of water quality:a, Under different circumstances rainfall intensity, the total amount of non-point source pollution discharged into the river with receiving positive correlation; As the return period increases, the concentration of pollutants discharge ports also increased, but followed with a downward trend; the peak concentration of pollutants, will also appear in advance as return period increases.b, As the different functional areas of the study area is different, The units of the total area of erosion runoff pollutants are different too. Hospital sewage volume per unit area yield higher than other functional areas, and the area of the park the amount of other pollutants were lower than many other functional areas; pollutant load per unit area is also quite different, the approximate order functional areas pollutant emissions are: medical, residential areas, cultural areas, gas stations, park.c, Under the 1-year return period rainfall under 2 hours, the total production of rainfall runoff pollution is significantly reduced as the green area increase. |
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