Study on pollution problems and countermeasures for the Nanpan River(source of the Pearl River)Basin in Qujing
The Nanpan River is the source of the Pearl River,and the mother river of the people of Qujing,Yunnan.The comprehensive and systematic governance of the Nanpan River is of significance to the improvement of the ecological environment of Qujing and the sustainable development of local economy and society.In order to accurately grasp the conditions of water pollution in the Nanpan River Basin,this study analyzes in detail the spatial and temporal changes in local water quality,the overflows of the urban pipe network during rainfall,the distribution of sewage outlets at river banks and pollutant emissions,the coverage and leakage of the combined sewage interception pipe network,and the coordination of operations of dams on the main stream of the Nanpan River.The results of the analysis show that the water quality of the Nanpan River Basin is at poor-class V,which means it has been heavily polluted.The water quality during the dry season is worse than that of the rainy season;The water quality of tributaries is worse than that of the main stream;And the water quality in the downstream is worse than that of the upstream.The main nonconforming factors are NH3-N and TP.When the rainfall in urban areas is higher than about 10 mm,large amounts of domestic sewage overflow from the rainwater outlets of some tributaries(such as the Baishi River),and the combined rainwater and sewerage system is insufficient to cope with the rainy weather.There are 225 outlets along the main stream and tributaries.The water quality conforming rate for sampling 50 outlets is about 24%.Nonconforming emissions are a universal problem.Qujing city lags behind in urban infrastructure.About 30 km2 of its built-up area uses a combined rainwater and sewerage system,and about 40%of the area is still not covered by a sewage interception pipe network.The amount of water resource per capita in the urban area is 760 m3,which is only 15.6%of the average of Yunnan and 36%of the average of the whole country.Water storage capacities of dams on the river can meet the water needs of agricultural irrigation,but the coordination of operations of the dams is poor,and thus ecological flowers required for the river are not secured.It is suggested to adopt the river chief system as the starting point to strengthen the control over pollution of source points of industries and urban life,so as to optimize the allocation of regional water resources,improve the comprehensive governance and management mechanisms of riverways,and build an efficient execution system for such governance.Only with a governance pattern that allows society-wide participation,the water and ecological environment of Nanpan River can really benefit the people.
Source of the Pearl RiverNanpan Riverpollution characteristicsrainfalldrain outlets
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