Optimized Design Of Diversion Of Water To Control Sediment Of Yao River Dam Diversion Type Power Station On Nanya River

Southwest of our country water resources is very abundance. Even river contain a small quantity of alluvium, but annual sediment discharge suspension load is very larger because of a great deal water flow and gradient ratio steep. If reservoir capacity is smaller relatively, alluvium issue will not allow be neglect. Moreover, the bed load of mountainous area river that threaten water power station need be treated seriously.Building low dam diversion pivot on the river that of gradient ratio steep > bed material roughness and bed load movement acuteness is characteristic in Southwest medium size water power station. The clarification basin is built in upstream nosing pivot in order to relieve alluvium abrasion to turbine. Since complicated alluvium issue need to be solved, clarification basin is costly and construction work is severe disturbed, water power station hardly is built on the river in other country. Although much experience is already accumulated in the aspect by our country, canceling clarification basin is a first in the world.This paper basing on experience of some power station in Southwest, collect actual measurement date that turbine and through-water building is abraded by alluvium, and analyze successful and unsuccessful experience of existing diversion sand control establishment. Basing on these, alluvium character of Yao river dam reservoir is analyzed according to basal theory of alluvium move, a way that optimize design of diversion sand control is put forward, reasonable method of reservoir move mode is established to ensure that rough sand(d>0.25mm) can't enter into tewel, and so that costly underground clarification basin will be canceled. Theory and prototype date are analyzed, at the same time the suppose that cancel underground clarification basin is proved by model test of Yao river dam power station reservoir drop sands and gate bay sweep away sands.The feasibility that cancel underground clarification basin have been approved by theory analysis ^ prototype date analysis and model test analysis , and by comparing clarification basin and sediment outflow index in reservoir with in underground in many respect , clarification basin and sediment outflow effect is credible, management is flexible and convenient, turbine through repair cycle will be prolonged, electric energy loss will be reduced, and about 50% investment of upstream nosing pivot will be saved (about sum to 3400 ten thousand yuan). The conclusion of the study has important significance for building the same type power station in the future.