Changes Of Boundary Conditions Influence On Flood Transverse Scouring And Silting Effect On Inner Mongolia Reach

Natural conditions change and human activities have caused heavy sedimentation, channel shrinking and bed of river elevating. Recently, flood risk is increasing and disasters that lead to great threats in production and life constantly were increasing in the ice flood season. In view of yellow river xiaolangdi reservoir scouring lower yellow river obtained successfully experience. Some scholar proposed flood scouring is an important method in order to govern channel, defense disaster, alleviate sedimentation and recover channel, and water resources is scarcity in upper yellow river, so flood scouring effect appears more important.Flood scouring influenced by channel geometry was discussed in order to analysis effect of transverse scouring. Channel boundary changing characteristics were firstly found out, then probing channel geometry changing influenced on transverse scouring by building the relation of change of section area during once flood and influencing factors, then predicting artificial flood scouring effect and supplying decision basis for channel governing operator. Conclusions were obtained by anglicizing:1) The process of deposition in Inner Mongolia was obvious by quantifying change of section area during once flood that was proposed, and then according to this method, Inner Mongolia reach have experienced 1976-1985 equilibrium phase and period of violent revolution, then enter into 2000-2006 equilibrium phase. Regime coefficient became larger, section became wider and was not good for sediment transport.2) Relation of change of section area during once flood and influencing factors was built. Change of section area was proportional to flood kinetic energy, was inversely proportional to regime coefficient and initial section area. Under current channel form, flood scouring makes section area expand but containing pollution ability decreased and easily deposition again.3) Prediction on horizontal and longitudinal on the assumption that six groups' virtual artificial floods scoured. On the transverse direction, stepwise regression and Monte Carlo was used for probability prediction. On the longitudinal direction, sediment discharge balance method was used. Virtual artificial flood scouring effect was not nakedness' and water consumption was large. Governing ten tributaries and desert, saving water and decreasing Qintongxia sediment ejection.