关于黄河水沙形势及对策的思考

The Water and Sediment Situation and Countermeasure

水少沙多是黄河的突出特点。进入21世纪,黄河天然径流量减少了20%,取用水量却不断增加。近10 a黄河头道拐至花园口河段和全河的地表水资源利用率已分别达60%和80%,水少问题更加突出,缺水已经成为黄河流域面临的最大问题;节水潜力是有限的,将黄河下游分水指标过多调整给上中游又将导致不健康河段更长,因此建议尽快开工建设南水北调西线工程,并兴建多年调节水库,提高黄河蓄丰补枯的能力。2000-2019年,潼关年均输沙量仅2.45亿t/a,“沙多”压力有所缓解,但还原坝库拦沙量后的流域产沙量为5.64亿t/a,仍然远高于黄河下游的承受能力。未来,如果能将林草梯田覆盖程度提高至理想情景,流域产沙量可降低至4亿~5亿t/a;但是,黄土高原植被极易受人畜破坏而退化,若退化至2010年水平,“龙华河洑”四站沙量将反弹至6.7亿~7.1亿t/a。因此,黄河水沙调控工程和防洪工程的规划设计必须为未来沙量反弹留足空间。为控制入黄沙量在低位水平、支撑黄河长治久安,黄土高原应优先重视现状林草植被的维护,并改进黄土丘陵沟壑区第五副区产沙的控制措施。

The outstanding features of the Yellow River are less water and more sediment.From 2000 till now,the natural runoff of the Yellow River has decreased by 20%but the water withdrawal has been increasing.In recent 10 years,the surface water utilization rate of the middle reaches from Toudaoguai to Huayuankou of the whole river has reached to 60%and 80%respectively,thus water shortage has become the biggest problem of the Yellow River Basin.Since the water⁃saving potential is limited,and it would make longer unhealthy reaches if we transfer part of the water rights from the people around the lower reaches to the people around upper and middle reaches,this paper suggested to build the West Route Project of the South⁃to⁃North Water Transfer as soon as possible and build carry⁃over storage reservoirs to improve the runoff supplying ability during dry years.From 2000 to 2019,the sediment load of the Yellow River was only 0.245 billion t,the sediment pressure had been eased.But if we restore the sediment intercepted by dams,we would find that the actual produced sediment of the Loess Plateau should be 0.564 billion t,which is far beyond the riverbed’s bearing capacity of the lower Yellow River.In the future,the sediment production load would be decreased to 0.4-0.5 billion t if the vegetation and terrace grow to its ideal coverage.But the vegetation of the Loess Plateau is easy to deteriorate when disturbed by human and livestock.The sediment load of the Yellow River would rebound to 0.67-0.71 bil⁃lion t even if the vegetation has merely deteriorate to the level of the year 2010.Therefore,this paper agreed to plan and design the key water and sediment regulation projects according to the present low sediment level temporarily,but we must reserve enough room for rebuilding to meet the future challenge of sediment rebounding.In order to control the sediment load at the low level and to maintain the Yellow River safe⁃ty,preserving the current vegetation should be the first countermeasure taken in Loess Plateau and the measures of controlling gully⁃bank and riverside⁃bank erosion should be improved in the No.5 sub⁃region of gullied rolling loess area.