Research And Application Of The Minimum Ecological Discharge Curve Model Of Small Hydropower

At early 2019,the MWR together with relevant ministries and commissions,held a joint video meeting in Beijing to deploy and advance the cleaning and rectification work of outstanding problems of SHP along Yangtze River economic belt.At present,there are many industrial standards and norms on the calculation of minimum ecological flow(MEF)in China,and most of the results are the application of a certain value as the MEF.In the administrative regulations issued by various regions,hydrologic calculation methods are generally adopted,and most of them take no less than 10%of the natural average annual discharge of river as the MEF.However,some seasonal rivers in the north,some rivers in dry areas in the northwest,and some rivers in the southwest with large difference between wet season and dry season,there is little or even no water upstream,and the MEF would not satisfy the standard at all.It is unreasonable to simply use a certain numerical value as the MEF.The research contents of this thesis mainly include the following aspects.(1)Research on MEF calculation methods at domestic and overseas.This thesis analyzes and compares several main calculation methods,and puts forward the applicability and existing problems of various evaluation methods.(2)Research on the concept and model of MEF curve.This thesis confirms a series of conditions that affecting the MEF,and puts forward the concept of MEF curve and establishes the mathematical model of the MEF.(3)Application of MEF curve in green SHP evaluation.This paper briefly introduces the concept and development history of green SHP in China,as well as the calculation method and satisfaction calculation method of MEF in the evaluation standard of green SHP,to compare and analyze their advantages and disadvantages.(4)Case analysis of power station.According to data such as minimum continuous 30-day average flow method,7Q10 method,Tennant method and so on,to draw the MEF curve of the case power station according to mathematical model calculation.Proposing a simplified method of MEF curve model,which is convenient for application in project management.To combine with the MEF calculation method of existing green SHP evaluation criterion,and calculate the satisfaction condition respectively.Based on the contrast analysis of two kinds of results,preliminary discussion on the application of MEF curve in the green SHP evaluation.