Prediction And Evaluation Of Caohai Water Quality Improvement Effect In The Water Diversion Project In Central Yunnan

DianChi is the largest fresh water lake in Yunnan Province,and has the urban water supply,industrial and agricultural water,to regulate,flood control,tourism,aquaculture and other functions,is the basic condition of the survival and development of kunming,plays an important role in the climate regulation of Dianchi watershed.So far,there are nearly 50 billion has been used in the governance of DianChi.Six projects that "wastewater interception around lake,draw water diversion and water saving,regulation of rivers into the lake,agriculture and rural areas non-point source management,ecological restoration,ecological dredging and construction" has been fully implemented.Dianchi Lake water quality gradually improved.In particular,Niulan jiang-Dianchi lake filling water engineering was implemented in the 2013,replaced and restored WaiHai water,so that WaiHai water quality was significantly better and improve faster,water quality gradually transform worse V to V.However,in view of the Niulan jiang river supply water quantity and estuaries of lake be limited,the replacement and restoration of water body was restricted,the overall improvement of the sea water quality is poor.At present,the DianChi lake governance has entered a crucial stage.In the order to accelerate DianChi governance and reach the water quality of DianChi water function division,DianChi governance is comprehensively promoted precision,efficient and tackling measures.Based on the current situation of DianChi governance,inter-basin water transfer exchange and repair Dianchi Lake water,and is is the most direct and effective way to control Dianchi Lake.During the "13th Five-Year Plan" period,in order to alleviate the contradiction of water consumption in the central Yunan,Yunnan Province will implemen the Water Diversion Project in Central Yunnan,and plan to provide 3.59 million cubic meters supplemental wate to the ecological use water of DianChi.Complement each other with the Niulan jiang-Dianchi water supply project,to greatly improve DianChi water environment.In 2016,Yunnan province Explicitly take the comprehensive improvement of CaoHai water environment as the first priority and tackling the difficult breakthrough of DaiChi governance work.CaoHai water quality has long been in the worse V,governance work is imminent.In order to improve the water quality of CaoHai and accelerate the transformation of water ecological environment,combined with the upcoming DianZhong water diversion strategy,this paper through the optimization of water diversion and water allocation program,to explore the optimal replacement and restoration of CaoHai water quality in the Water Diversion Project in Central Yunnan,and implemen the accurate replacement and restoration of CaoHai governance,give Dianchi lake water environment governance provide technical support and decision support.In this paper,the main research results are:(1)In view of the Water Diversion Project in Central Yunnan,this paper design Daguan river as irrigating intake,Xiyuansuidao river as drainage outlet,and the replacement effect of the CaoHai water quality is better.(2)After the Water Diversion Project in Central Yunnan exchange CaoHai lake water,and in the absence of external pollutants into the grass sea of the ideal state,form Daguan river diversion 8.5m3/s,the CODcr,TN,TP indicators in the lake body reach III water quality indicators.(3)From the Daguan River diversion,mainly through the role of diffusion and dilution to exchange and repair CaoHai southwest region water body,the replacement rate of the water body is relatively slow and the the replacement of the water body is more difficult,so increasing the governance of the region before the implementation of the Water Diversion Project in Central Yunnan,or according to the replacement effect of water distribution can be considered to add a Wangjiaduiqu irrigating intake.(4)Using Mike21 model to simulate the effect of CaoHai lake ecological replenishment project,which can better reflect the diffusion law of pollutants in lakes,the simulation results are good,and shows that the application of' two-dimensional hydrodynamic water quality model in shallow lakes is reasonable and feasible.