黄河水沙变化与下游河道改造

20世纪80年代中期以来,进入黄河的水沙量及其过程发生了重大变化,潼关水文站水量和输沙量大幅下降,已由1919~1959年期间的平均水量426亿m3/年、输沙量16亿t/年下降到2000~2012年的231亿m3/年和2.76亿t/年,随着黄河上中游水土保持和生态建设的持续开展,预计未来50~100年潼关站年平均水量和输沙量将逐步稳定在210亿m3/年左右和3亿t/年左右。水沙变化关系到治黄方略的制定,关系到黄河的长治久安。为了顺应黄河水沙的变化,确保黄河防洪安全,实现下游河道不改道、河床不抬高的治理目标,本文提出了新的水沙条件下黄河下游河道治理的总体思路是:改造河道、解放滩区。具体措施包括:稳定主槽、缩窄河道、完建堤防、治理悬河、滩区分类。建议深入研究下游河道改造的方案与河道缩窄的可行性及其影响,为黄河下游河道改造提供科技支撑。

Changes in runoff and sediment loads of the Yellow River and its downstream channel reconstruction

Major changes in runoff and sediment loads of the Yellow River have been token place since the middle 1980s. The water and sediment dischages have been declined sharply at the Tongguan hydrological station，with average annual water dischage of 42.6 Gm3/a and annual sediment load of 1.6 Gt/a over the period of 1919~1959 decreasing to 23.1 Gm3/a and 0.276 Gt/a over the period of 2000~2012，respectively. It is expected that the average runoff and sediment loads at Tongguan Station will be gradually stabilized at about 21 Gm3/a and 0.3 Gt/a in the next 50 to 100 years with the persistent water and soil conservation practices and ecological construction in the upper and middle Yellow River. The changes in runoff and sediment loads are closly related to the strategy of the Yellow River management and the river’s long-term safty. To ensure the flood control safety and achieve the goals of river management with no diverting downstream channel and no raising riverbed by adapting to the changes in water and sediment discharges of the Yellow River，the author puts forwards a general thoughts of the Lower Yellow River management under the new water and sediment conditions，i.e. river channel reconstruction and floodplain liberation. Specific measures include： main channel stablized，river channel narrowed，dike construction completed，suspended river managed，and floodplain classification. It is suggested that the plan of the Lower Yellow River channel reconstruction，the feasibility of river channel shrinkage and their effects be studied in-depth to provide scientific and technological support for the Lower Yellow River channel reconstruction.