近几年来，由于渭河下游来水来沙量的减少，加之水沙组合的特殊变化，使河槽淤积加重，过洪能力降低，平滩流量大幅度减小，同流量水位抬高，河道萎缩严重。河道萎缩使洪峰削减率增大，传播时间加长，对渭河下游防洪安全造成较大威胁。 In recent years, due to the decrease of incoming water and sediment in the lower reaches of the Weihe River, combined with the special changes in water and sediment mix, siltation of the river channel is aggravated, the flood capacity is reduced, the flow of flat beach is greatly reduced, . The shrinkage of the river channel will increase the reduction rate of flood peak and prolong the propagation time, posing a great threat to the flood control safety in the lower reaches of the Weihe River.