Research On Waterway Regulation Of Complex Reach Downstream Of The Canalized Hydraulic Project

From Qingyuan to Shaoguan, the reach of Beijiang midstream is about217kmwhich is water transportation artery connecting "Pearl River Delta" of northernGuangdong Province, and it plays an important role in material intercourse，culturebroadcast，economic development for people. But for a long time, since low-gradechannel, poor infrastructure, it can not meet the need for continued rapid growth intraffic. Through maritime construction project, it could enhance waterway levels,improve navigation conditions, expand navigation ability and promote social andeconomic development.The19km downstream of Baishiyao project consists of tailwater unconvergedsection, fluctuating backwater area, backwater Area，its water and sediment conditionsare very complex, so it is one of the important and difficult point of navigationConstruction. on the basis, this paper is to research waterway regulation measures.This paper applies riverbed evolution analysis, mathematical model calculationcombining with physical model test, and achieved the following main results:(1) Based on waterway regulation, it is useful to optimize regulation, improveproject layout, reinforcement stability side beaches, improve remediation level, andenhance transport capacity, maintain waterway stability.(2) After waterway regulation, water level lands obviously in dry season, flowvelocity increases slightly, and it is helpful to reduce sedimentation and maintain stabletrench.(3) The waterway regulation lines rely on the dominant riparian. ExcavatedChannel are arranged along the river thalweg and regulation lines are narrowed withappropriate width so that water level were raised. The fixed bed model test shows that:After renovation, the flow dynamic axis is consistent with trend of excavated channel indry water phase and middle water phase. The water concentrate in the navigationchannel and mainstream direction has small angle with axis of excavated channel onsmooth river. Velocity on channel are lager than the stopped velocity of sediment onchannel segment from dam to guanyinzhou and it is also larger than before. Velocity onchannel between guanyinyan and daluodu has little change, it may increase or maydecrease.But scope of large velocity is larger. velocity on channel below daluodu has alittle increased，but it is limited by backwater of feilaixia which is a huge waterconservancy hub. (4) The movable bed tests shows that: scheme two has the better result, it meetsthe basical requirements of design and it’s siltation volume of sediment in three years is112800m3（37600m3per annum）which is35800m3reduced by scheme one（11900m3per annum）.(5) There have little change before and after regulation engineering about Waterlevel along river and velocity in flood period on scheme two and also have slight effecton stability of slope.(6) Based on comprehensive comparing in technical and economic,i suggest thatscheme two as the recommended scheme,because of it’s better result on the river whichhas regulation engineering downstream Baishiyao water conservancy hub, on the otherhand, it provides a reference for design.