Study On The Coordinated Development Of Water Quality And Social Economy In Karst Mountain Basin

Pingzhai reservoir is the source reservoir of Qianzhong water conservancy project.To some extent,the quality of water environment in the basin will affect the safety of water use in the lower reaches and even in the middle of Guizhou.The protection of water environment in the basin is of great practical significance.The reservoir basin is located in the western mountainous area of Guizhou Province,with a relatively low level of economic development.The hope of getting rid of poverty and developing economy is particularly urgent.At the same time,the basin is located in the concentrated area of "Yunnan Guangxi Guizhou rocky desertification".The fragile ecological environment puts forward a certain test for the local infrastructure construction and social and economic development.Under the background of "great ecology and great poverty alleviation" in Guizhou Province,how to coordinate the relationship between water environment quality and social and economic development has become a hot issue in watershed research.Based on the measured water quality data and socio-economic statistical data of Pingzhai reservoir basin in 2018,combined with environmental science,environmental economics,statistics and other related theories,use geographic information system(GIS)to extract water system and divide River Basin,and determine the basin range andvillages and towns involved in Pingzhai reservoir.Based on the preliminary analysis of the main pollutants in the river basin,the pollution sources such as chemical fertilizer loss,livestock breeding and residents' domestic sewage were investigated in the township as a unit.The equal standard pollution load method was used to calculate the equal standard pollution load ratio of the pollutants in each township.The contribution of the pollution discharge of each township was analyzed by using GIS space technology to determine the theoretical key pollution discharge area.Combined with the social and economic development of each township,the coupling and coordination measurement model is constructed by comprehensive principal component analysis.The water environment and social and economic evaluation values of different river reaches and townships in 2018 are obtained,and the coupling and coordination of water environment and social economy of upstream river basin are analyzed.As a reference,the new model of sustainable and coordinated development of water environment and social economy of river basin is explored.The results show that:(1)the spatial change of water quality in the upper and lower reaches of Pingzhai reservoir basin is better than that in the upper reaches.The main reason is that most of the sampling points in the upper reaches are located near the cities and towns,and the human activities are intensive.The middle and lower reaches have experiencedthe supply of clear tributaries and rainwater.The water quality is relatively poor in the normal water period,followed by the low water period,and relatively good in the high water period.The watershed is generally affected by point source and non-point source pollution.Among the sub basins,the water quality of Nayong river is relatively poor,while that of shuigong River and Hujia river is relatively good.The pollution characteristics of Nayong River and Baishui River are similar to that of the whole basin.The water quality of Zhangwei river changes with the water volume of the basin,and the point source pollution and direct sewage discharge have a great impact on the water quality;(2)the total equivalent pollution load per unit area of Nayong River,shuigong River and Baishui River is large,and the theoretical single area pollution intensity of the basin is relatively large,and the pollutants per unit area of Zhangwei River and Hujia River Basin enter the river The intensity is relatively small.Compared with the water quality of each sub basin,it can be concluded that there are pollution factors in Nayong River,Baishui River and Zhangwei river basins,such as lack of sewage treatment facilities,direct sewage discharge,loss of chemical fertilizer on sloping land,etc.,and further measures need to be taken in pollution prevention and water environment protection.(3)Except for shuigong River,the coupling degree of water environment and social economy in other sub basins is incongruous,and the types of incongruity are mainly dividedinto three categories:(1)lag type of water environment,taking some towns in Nayong River Basin as an example;(2)lag type of social economy,taking some towns in Hujia River basin as an example;(3)lag type of water environment and social economy,taking Zhangwei River Basin as an example.On the basis of water environment protection and river basin pollution control,uncoordinated regions should develop social economy in various ways,and promote the ecological protection and construction of karst poverty-stricken mountainous areas,and realize the local scientific and sustainable development.