Water Environment Quality Evaluation Of The Nanguang River In Gao County

Nanguang River has a total length of 213 km and the section in Gao County is83 km.It is the first tributary of the Yangtze River,it plays a decisive role in the water environment of the upper reaches of the Yangtze River.However,with the economic and social development of Gao County,the section in Gao County of Nanguang River is faced with problems such as water shortage,water pollution and water environment deterioration,which have affected people's production and life and restricted the economic and social development at the same time.Therefore,it has far-reaching practical significanceto for promoting the sustainable development of social economy of Gao County and guarantee the upstream of the water quality of Yangtze River to further understand and grasp the water quality of Nanguang River section in Gao County,analyse the present situation and existing problems of the water environment in an all-round way,formulate feasible measures to water environmental protection and management,prevent the deterioration of water environment effectively.Based on the investigation of the water environment problems of Gao County and according to the basin characteristics,branch distribution and hydropower station location of Nanguang River,we practice an monitor water quality index deviding the river into Zuishang-Zantan township section,Gongxi-Wenjiang town section,Laifu town-Nanguang town section;with the data from 2013 to 2017,we analyze the changing trend of indicators of different monitoring sections at the same time and the same monitoring section at different times to get the changing trend of wet season,dry season and medium season.In the past five years,we have identified the water quality of the three cross sections by fussy evaluation method and gotten the pollution level of the three cross sections by comprehensive pollution index method;we raise the measures and solutions to water pollution according to evaluation results of water quality and source of pollution.The research results of the thesis show that during the same period,the water quality of Laifu town – Nanguang section is the poorest and the pollution is relatively serious;In different years,the overall situation in the past five years is that the waterquality is getting worse year by year,reaching the worst in 2016,and improving again in 2017.In different water periods of the same year,the pollution was the least in the wet season,followed by the plain season,and the most serious in the dry season.According to the calculation of pollutant sharing rate,the main pollution factors in the upper reaches of Gao County section of Nanguang River are ammonia nitrogen and total phosphorus,the middle reaches are dissolved oxygen and ammonia nitrogen,and the lower reaches are dissolved oxygen,ammonia nitrogen and chemical oxygen demand.To achieve the pollution control target of water environment,this paper puts forward three ideas such as strengthening source protection,paying attention to the environment landscape construction of midstream and the restoring ecological environment.Besides,we must implement five measures including completely intercepting pollution,developing the technology of recycling pollutant water,reinforcing the construction of ecological bank protection,regulating the water yield of Gao County section of Nanguang River and dredging the river.