Water Environment Carrying Capacity Of Lancang River Basin In Yunnan Province Based On GIS

In recent years,with the development of hydropower stations in the Lancang River Basin,road construction,population growth,the process of urbanization is accelerating,water environment problems such as water demand increasing,water pollution and deterioration of water ecosystems have become increasingly prominent,it affect the water environmment and sustainable development of social economy in the basin.It is of great significance to discuss the carrying capacity of water environment and to coordinate the water environment and the sustainable development of human society and economy in the basin.Taking the Lancang river basin in Yunnan province as a case,and the water environment and human socio-economic sustainable development as the goal.Applying the water environmental carrying capacity evaluation model to analysis the trends of water environmental carrying capacity in the Lancang river basin in Yunnan province since 2007 to 2014,and ArcGIS to discuss the spatial distribution and time variation of water environment carrying capacity of Lancang river basin in Yunnan province,and finally the gray prediction model to predict the water environmental carrying capacity in the next 6 years.The main results of this study include as follow:(1)From the time of view,82.05%(32)counties water environment carrying capacity was decreased,17.95%(7)counties water environment carrying capacity remains unchanged or slightly increased of the Lancang river basin in Yunnan province since 2007 to 2014.Counties with the largest reduction in the carrying capacity of the water environment were Dali,Linxiang,Changning,Binchuan,Fengqing Jinggu and Jiangcheng,which are due to the increase of waste water discharge,the acceleration of urbanization,the increase of population,industrial development on the amount of water and environmental pollution capacity caused by the enormous pressure.County with the largest increase in the carrying capacity of the water environment were Jinghong,an increase of 0.12,which is that the comprehensive implementation of comprehensive urban and rural environmental remediation,industrial and agricultural water consumption decreased,environmental awareness increased,but also increased the industrial wastewater and urban sewage treatment capacity,by 2014 the city's urban sewage treatment rate of 77.6%and garbage treatment rate of 100%.(2)From the view of space,the high carrying capacity of water environment is concentrated in the upper reaches of Lancang river basin in Yunnan province,including Deqin,Weixi,Yangbi,Jianchuan and so on,water environment carrying capacity values are higher than 0.7(0.7<Reecc<1,the water environment in a optimum state),in the upper reaches of the mountainous steep,coupled with high latitude,high altitude,mainly in agriculture and tourism development,industrial development,environmental pollution is relatively small,human activities have little impact on the water environment.The low carrying capacity of water environment is concentrated in the middle and lower reaches of Lancang river basin in Yunnan province,including Simao,Jinghong and Longyang and so on,among which Jinghong and Longyang have the weakest water carrying capacity,which are lower than 0.33,because of the city and town more,rural economy developed,a large munber of township enterprises,industry and mining are more developed,population density,high level of urbanization,environmental pollution and human activities on the water environment poses a greater threat.(3)The optimal environment of water environment in 2015-2020 is concentrated in Deqin County,Weixi County,Lanping County and Ximeng County.The water environment state is more fragile in Dali,Longyang,Linxiang and Simao districts The Mainly in the county and city economy is more developed,the population is relatively concentrated,more towns,industry and agriculture is more developed,exacerbated the shortage of water resources and water pollution problems,affecting its water environment comprehensive carrying capacity.Deqing County,Weixi County,Lanping County,Ximeng County,vegetation coverage,water resources,urban population is small,mainly in agriculture,human activities have little impact on the water environment.(4)In the upper reaches of Lancang river basin in Yunnan province,sparse population,rich in water resources,water resources development and utilization of low,the slow pace of economic development is relative to middle and lower reaches of the river.Middle and lower reaches of the river,domestic sewage and domestic waste,industrial production of industrial wastewater,agricultural production activities brought about pesticide residues,fertilizer loss and other pollutants continue to increase,environmental capacity caused by a certain pressure.At the same time,the increase of industrial and agricultural wastewater and domestic sewage discharge has brought great pressure on the water environment,which leads to the decrease of water environment quality,and the corresponding management system and legal system are the main reasons leading to the fragile water environment.