渭河下游河道输沙特性与形成窄深河槽的原因

通过实测资料分析得出：含沙量２００ｋｇ／ｍ＾３以上的洪水，河道排沙能力强，５００ｍ＾３／ｓ流量的排沙比可达１００％；含沙量１００－２００ｋｇ／ｍ＾３的洪水，８００－１０００ｍ＾３／ｓ流量的排沙比才能达到１００％，河槽排沙能力低，主槽淤积机会多，数量大，对河道不利；高含沙量小水，主槽淤积严重；高含沙量大洪水淤滩刷槽，形成窄深河槽。河岸抗冲稳定性较强，并经常出现高含沙量大洪水，是形成渭河下淤窄深河槽的

Characteristics of Sediment Transport and Reasons for Forming a Narrow and Deep Channel in the Lower Wei River

It is obtained through the observed data that the sediment discharging capacity of the river is great when sediment concentration of a flood is more than 200kg/m3 and sediment deliervy ratio of 500m3/s, discharge can reach 100 %: for the flood of sediment concentration 100--200kg/m3, the sediment delivery ratio of discharge 800-1000 m3/s. can reach 100%. resulting in small sediment discharging capacity of the channel, more opportunities and greater volume of siltation in the main channel; the siltation in the main channel is serious when it is a small flood with high sediment concentration and: it silts the floodplains.scours the channel and forms a narrow and deep channel when it is a big flood with high sediment concentration. The strong scour resistance and stability of the banks and coming big floods always with high sediment concentration are the key fators for forming a narrow and deep channel in the lower wei River.