The Analysis Of Rainfall Runoff Pollution Of The Typical Area In The Middle Reaches Area Of Haihe River Based On RS And SWMM

As one of Chinese seven major river systems, the Haihe River is also the largest river system in North China. The main stream mainly flows through urban area of Tianjin and Binhai New Area and, ultimately, imports Bohai Sea. Among the top ten watersheds of China, Haihe River Basin is the most polluted area. In the middle reaches of the Haihe River area, due to the concentrated industrial parks and the complex environment of tributaries, the composite pollution characteristics is very obvious. Tianjin Airport Economic Zone is a typical area close to the middle reaches of Haihe River, the non-point source pollution, including sewage and storm runoff, causes serious composite pollution for the Haihe River and the tributary streams. By exploring the characteristic of the non-point source pollution caused by the storm runoff, and targeted developing the runoff pollution control technology, the pollution load of the middle reaches of the Haihe River can be effectively reduced.In this paper, based on the GIS and RS technology, the underlying surface of the study area was extracted. At the same time, the runoff pollution characteristic of different underlying surfaces was analyzed. Base on the above works, a rainwater runoff model—SWMM, which can simulate storm runoff and runoff pollution of the study area, was established. The main works and conclusions can be seen from the following. First of all, based on RS and GIS technology, the underlying surface of study area was extracted by using WorldView-II high resolution remote sensing image. According to the demand of the model and the actual situation of the study area, three kinds of underlying surface, greenbelt, impervious tiles and others were chosen for the typical underlying surface of Tianjin Airport Economic Zone. Secondly, the pollutants output characteristics of different underlying surface were explored. The simulated rainfall experiment was developed by using an artificial simulated rainfall device, based on which the EMC values of different underlying surface contaminants were calculated. According to the result, the concentration of TP in the greenbelt runoff is obviously higher than the other two underlying surfaces. At last, the SWMM model of the study area was established to simulate the stormwater runoff. The results show that the permeability of the study area is good, and the runoff lasted more than 10 hours. The contaminants increased rapidly at the early runoff, and the variation trend of the three contaminants was same. According to the results of the runoff water quality assessment, the runoff from all of the four outfalls were polluted seriously, especially the COD. The simulation results of different return periods show that the greater the return period, the larger the runoff was, and the more serious the runoff pollution was.