Research On Determination Method Of Designed Level Of Port Engineeirng In Fluctuating Backwater Area Of Reservoir

The hydrological characteristics of natural river have been changed greatly afterbuilding hydro-junction in mountainous river, while the fluctuating backwater areawhich between natural river and reservoir present typically double flow characteristics.In hydraulic engineering, the determination method of designed level of portengineering in natural river and reservoir is relatively unified; however, thedetermination method designed level of port engineering in fluctuating backwater areais still being explored. Thus, it become an engineering problem to be solved urgentlyhow to determine the designed level of port engineering in fluctuating backwater areareasonably. This paper analysis to determination of designed level of port engineering influctuating backwater area by time series model, flow mathematical model andfrequency analysis combined with the discharge data of hydrologic station in upstreamof reservoir. The main research contents include:(1) In order to establish discharge time series model of mountainous river, thispaper analyses the periodicity of the discharge data of mountainous river and introducedthe auto regressive models combined with measured discharge data. Then the originaldata can be fitted and forecasted to make up for the defects which hydrological datacan’t accord with the standard requirement.(2) This paper calibrated the hydraulic parameters of the river in fluctuatingbackwater area by measured data. A one dimensional steady non-uniform flow model isestablished to calculate the time series of stage by using HEC-RAS. It provided enoughdata for calculating designed level of port engineering.(3) By summarized existing methods of calculating designed level, this paperanalyses the difference and connection between instantaneous flood return periodmethod and ten days main high level frequency method when calculating designed highlevel. Also analyses the difference and connection between synthetic duration curvemethod and duration-frequency method when calculating designed high level low level.The variation characteristics of port engineering in fluctuating backwater area afterreservoir filled and in natural state are mainly compared. Then the determinationmethod of designed level of port engineering in fluctuating backwater area can beproposed on the basis of before.This paper proposed the determination method of designed level which can applied to port engineering in fluctuating backwater area, it provides Theoretical Support fordetermination of designed level of port engineering in fluctuating backwater area insouthwest china.