Study On Hydrodynamic Characteristics And Eutrophication Mechanism And Control Measures Of Shallow Lakes

The lake is the most frequent place for human activities.Under the double stress of human disturbance and natural activity,the lake has a series of environmental and ecological problems.Eutrophication is the most prominent.Therefore the study on the eutrophication of lakes is the urgent and important content for the most current research in lakes.The use of water environment mathematical model is one of the important methods of lake eutrophication research.This paper takes Wuxing lake in Yongji city of Shanxi Province as the research object.However,the ecological and ecological information about the lake is very lacking,coupled with serious water pollution.The phenomenon of water bloom has been took place many times.The ecosystem was extremely fragile,which had caused great difficulty on Ecological management.Therefore,the research group began to conduct a comprehensive system of Wuxing lake field investigation and sampling from March,2015 and analyzed the existing water environment problems of Wuxing lake as well as studied the hydrodynamic characteristics,the formation mechanism of eutrophication and control measures.The research group conducted a water warning research of the bloom on the lack of data region.The main research contents are based on:The paper analysis the temporal and spatial variation of the lake water environment based on the hydrological and water quality data in May,1990 to April,2016.According to the characteristics of the river and a lot of Su river water quality monitoring indicators,Wuxing water quality monitoring indicators are less and the indicators are much higher than the V class of water.The improved LVQ neural network and fuzzy neural network was used to study water quality of Su river,Wuxing lake,and the eutrophication status of Wuxing lake,which was analyzed by comprehensive nutrition index method.The study laid the foundation for the scientific diagnosis of the existing water environment problems.The paper established the model of two-dimensional shallow water hydrodynamic under the unstructured grid of Wuxing Lake,which uses the measured water level data calibration parameters and validate the model.The calculated results agree well with the measured value(R2>0.9),and verifies that this model can better simulate the Wuxing Lake hydrodynamic conditions.This model is used to study the hydrodynamic characteristics of the Yellow River before and after the maximum rainfall,as well as the formation process of the wind circulation in Wuxing lake analyzed.Finally,considering the wind speed and direction,lake boundary,runoff into the lake,water diversion of Wuxing lake flow effect,and make up for the lake boundary as well as water diversion effect on lake water power.This paper analyzed the formation reason of Wuxing lake from the relationship between external conditions,the source of nutrients and nutrients as well as eutrophication and so on.It analyzed the influencing factors of the eutrophication of Wuxing lake to determine the effect of different influencing factors on the eutrophication of Wuxing lake.In order to solve the problem of lack of data and make use of data supplement theory to make up the problem of small amount of data in Wuxing lake,the paper established particle swarm optimization algorithm to optimize BP neural network model.Then it carried out early warning research on the risk of Wuxing water bloom to improve the decision-making ability of Wuxing lake management department,reduce the ecological hazards and health risks associated with bloom.According to the characteristics and pollution characteristics of Wuxing lake,secondary development suit eutrophication model for Wuxing lake.Using the actual monitoring data for parameter determination and model validation,it was found that the calculated values were in good agreement with the measured values,which indicated that the model was suitable for the ecological research of Wuxing lake.Based on the actual situation of Wuxing lake,the feasible and effective control scheme was given from the recent and long-term respectively.The eutrophication model of Wuxing lake was used to quantitatively study Wuxing lake water environment improvement effect under the recent,long-term(ecological water transfer and non-point source pollution control)control measures,which could provide technical support and theoretical basis for lake water ecological management.