Temporal Changes And Driving Forces Of The North Canal In River Water Quality

In this paper, the study object is the water quality of main rivers in North Canal water system. And the author gave an analysis and discussion for population, Three major industries and land-use coverage change's impact on water quality of main rivers in North Canal water system. The main conclusions are as follows:(1)Through the use of improved standard categories index in temporal-spatial water quality assessment of main rivers in North Canal water system, that: The water quality of North Canal water system had no significant improvement from the year 2000 to 2006. But the Qing River and the Liang-shui River had greatly improved especially in the year 2006. North Canal River was the only river that its water quality was in a worsening trend in this period. From the view of the relationship between spatial distribution of water quality and urban layout, the focus of water pollution changed from the city center to the outskirts.(2)2000~2006, the population had a rapid growth trend in North Canal Water System,but the growth is mainly in urban function expansion area and urban new district. The total population and the G value of water quality in the North Canal has a good linear correlation, and show that the population growth had negative impact on water quality in the canal. The tertiary industry is on the dominant place and growth trend in North Canal River basin. The third industry and G value of water quality of North Canal River have very good linear relationship. It should be noteworthy that the growth of the tertiary industry on North Canal River can also have a large negative impact on water quality. The total population, the tertiary industry and the North Canal water G values have been multiple linear regression models.(3)Urban and rural construction land and farmland are mainly two types of land use in North Canal River basin. The two types of land use have a significant impact on water quality. The existence of farm land has increased the total phosphorus concentration of monitoring sections downstream, and this concentration is higher than the cross-section under the influence of construction land. At the same time, compared with industrial land and residential land, the COD concentration of the monitoring sections under the influence of the former is higher than the latter. In the eight central district of Beijing, the size of relation grade between different land use types and water quality is construction land> forest land>green land> farmland> lake and reservoir>other land. The outside of the eight central district of Beijing is farmland>construction land> other land(4)Pollution control works and sewage treatment facilities play a vital on the North Canal River water quality, they can improve water quality of rivers quickly, and we should intensify efforts to do a good job in this regard.