The Impact Of Sediment Deposition To Water Intake Of Power Plant In The Fluctuating Backwater Area

Cool water is a necessary condition to ensure normal operation for Thermal powerplant,and the sand prevent condition of cool water is very important to ensure the powerplant operate safely. Currently,a lot of researches on water intaking and sand preventingfor small and medium in natural rivers, reservoirs and lakes plant while only few studyhas been taken for sediment problems about large rivers and large hub fluctuatingbackwater areas.The Yangtze River is the water source of Youxi jiangjin Huaneng Power Plant(phase I), changeable sediment conditions and highly sediment concentration for TheYangtze Rive,and project reach for the typical "S" type, river water and sedimentcondition are complex, controlled conditions more.It is necessary to take into accountthe natural conditions and subsequent changes in reservoir backwater area of sedimentmotion, siting difficulties. In view of this, we use data analysis, site survey, a long reachone-dimensional mathematical model and the small variability of river physical modeltest method of combining research, the main content and research results are as follows:â‘ Through data collection, site survey and river physical model test study, we getthe result that erosion and deposition is equilibrium for natural conditions of projectsedimentation.â‘¡Research on the sediment motion rules adopt long reach of the one-dimensionalmathematical model and physical model tests on a small river after impoundmentproject reach the XiaoNanHai,the results showed after XiaoNanHai impoundment,reservoir engineering changes in river backwater area with dual characteristics ofreservoirs and rivers, natural sedimentation equilibrium case will be broken. With thegrowth of the XiaoNanHai reservoir operation time, the siltation cumulative increasingfor engineering river.The silt sediment movement rule in general conformity with thedistribution reservoir sedimentation fluctuating backwater area: The sediment siltationrate pre fastest growth with operating years in theXiaoNanHai reservoir,but graduallydecreasing as the operation time increase; siltation convex bank mainly concentrated inthe corners, as well as broad and shallow beach side concave bank reflux slow flow area;with reservoir running time grows, the river will be further toward the straight, slightlycurved,and high beach trench direction, until it reaches a new equilibrium sedimentationso far. â‘¢Until the end Reservoir operation30years sediment will deposite obviously inthe water intake upstream of the proposed project wins dam, DouShaBa, GuanMaQi,JinGangTuoNei, JiuKuaiTian, YanBa and water intake downstream HuLuQiWei,MaFenTuo. but the water near the left bank of the trench near JinGangTuo mainstreamarea, large flow, sediment deposition is not easy to fall, which is about2km upstreamand downstream areas are not deposition, and the upstream and downstreamJinGangTuo deposition zone Huluqin deposition zone nor a downward or upward trend,river water intake sand better conditions, is an excellent intake water area.â‘£The water sources for proposed Project islarge river, and the water section at thetop follows the river bend mainstream area of the river upstream river floats downwardtransport of the necessary land, the proposed project using mushroom-head water intakehead structure offshore water, considering the mushroom head type intake sitingrequirements, water intake and sediment conditions combined with its shipping, flood,fish spawning and other effects, requiring mushroom head at the top elevation is nothigher than178.63m, silting height less than4m, foundation depth of not less than3m.This research can provides technical reference for lacation select and structurearragement for other projects locate in change backwater area.