Research Of Water Quality Evolution Law And Protection Countermeasures Of Xinlicheng Reservoir

Xinlicheng Reservoir is one of the main sources of water supply to the city of Changchun,the change of water quality directly threaten the water security of the citizen.In particular,the outbreak of cyanobacteria in 2007 caused the city to stop the water supply for 45 days,causing the community attach great importance.The research of water quality evolution,understand the characteristics of flow field and contaminant movement of Xinlicheng Reservoir can predict changes in water quality and provide a scientific basis for reservoir management and water environmental protection.During the study period,we collected the water quantity and quality data of Xinlicheng Reservoir from 2000~2016,it takes more than a year to complete five times field survey works for sample,analyzed 113 water samples and 29 sediment samples,laid 19 monitoring sections.The sampling time covered four seasons,including the wet and dry seasons,which makes the field samples more representative.On the basis of large number of field investigations and laboratory tests,the water quality factors variation with time and space in Xinlicheng Reservoir and the causes of such distribution were analyzed.Then,using the software Delft3 D to build water quality model,the hydrodynamic and water quality of Xinlicheng Reservoir were simulated,and predict the changes of water quality in next four yearsAimed at the characteristics of the water quality in Xilicheng Reservoir,the existing problem of reservoir is analyzed.According to the basic protection countermeasures of “inner treat and outer control”,propose creation of an artificial wetland ecology system,betterresults would be obtained by complete its design.Through the systematic study of the above content,mainly conclusion summarizedas follow:(1)Through the analysis of the water quality and sediment quality of Xinli Cheng Reservoir and the inflow river,the main substances are TP,TN,CODMn,Fe and Mn.(2)The chemical characteristics for of water from reservoir and warehousing river are analyzed by the three diagram method of Piper.The hydrochemical types of annual average in the reservoir is HCO3-Ca-Na,The hydrochemical types of annual average inYiTongRiver is HCO3-Ca,The hydrochemical types of annual average in YiDanRiver is HCO3-Ca,The hydrochemical types of annual average in JiaGuanRiver is HCO3-SO4-Ca-Na,The hydrochemical types of annual average in Emerging river is HCO3-SO4-Ca.In all warehousing rivers,YiTongRiver's water quantity is the biggest one,the Dan River is the second.The hydrochemical type of the New city reservoir is mainly affected by YiTongRiver and yi Dan River.(3)Seasonal dynamic changes of water quality are outstanding.pH?DO?BOD5?NH3-N?TFe and Mn is up to the maximum in winter,while CODMn is up to the maximum in summer.TN concentration increases with time,and TP concentration decrease over time.The values of TFe and Mn in winter were the highest,mainly due to endogenous release.The spatial distribution of the indicators of reservoir water at different periods is not very significant,which is closely related to hydrodynamic conditions,precipitation recharge,underwater terrain,biological activity,sediment release and sampling point arrangement.(4)Analysis and Evaluation of Eutrophication of Reservoir.Using Xinlicheng Reservoir water temperature?pH?Suspended Solids(SS)?Transparency(SD)?Chemical oxygen demand(CODMn)?Total Nitrogen(TN)?Total Phosphorus(TP)?Chlorophyll-a(Chl-a)et al,the effects of pollutant sources,plankton on eutrophication and eutrophication were systematically analyzed.The results showed that from 2003 to 2010,the water level of Xinlicheng reservoir was from light nutritious to mid nutritious.In 2007,peak cyanobacteria outbreaks were achieved,mainly due to excessive nitrogen and phosphorus,due to high water temperature and lack of fish filter effect.(5)Using the Delft3 D software to establish the water quality model,the two-dimensional hydrodynamic numerical simulation and the water quality simulation forecast of the Xinli Cheng reservoir are carried out,and the migration process of TN,TP and CODMn in the reservoir is obtained accurately.In 2012,respectively,to predict the concentration of dissolved water in the multi-year average,20% reduction,50% reduction,an increase of 50%,2013-2016 concentration trends,respectively,to class ?,? class,? class,standard.The forecast results show that effective control measures are needed to reduce the concentration of pollutants in the reservoir to ensure that the reservoir water quality meets the eligibility criteria.(6)The sources of reservoir pollution are mainly point source,non-point source pollution and reservoir endogenous release,and put forward a series of governancemeasures for source emission reduction,path block and end treatment.Aiming at the problem of eutrophication of reservoirs caused by excessive nitrogen and phosphorus,it is proposed to construct artificial wetland ecosystem program along the Yitong River,Yindan River and the tributary estuary in the upper reaches of the reservoir.The nitrogen and phosphorus pollutants are adsorbed and treated.Through harvesting plant,remove the primary protected area.After 2012-2013 construction,the actual construction of wetland area of 1843 hectares,planting trees,shrubs,reeds,lotus.Which reed,cattail 865 hectares,the annual absorption of nitrogen 45800 kg,phosphorus 11800 kg.2014-2016 water nitrogen and phosphorus were effectively controlled,water quality and stability,to class? water quality standards,eutrophication year by year to reduce.Artificial wetland ecosystem is easy to manage,quick,long-term operation,stable and effective,with good demonstration.