黄河宁蒙河段泥沙加入量分析及防治对策

利用1950—2005年黄河干流泥沙分布特征值资料与干流任意河段年平均泥沙加入公式对黄河干流宁蒙河段年平均泥沙加入进行了计算分析。结果表明,1950—2005年宁蒙河段每年都有大量泥沙加入,并且加入量随时间呈波动变化。通过数据分析与实地调查发现,造成该河段泥沙大量加入以及随时间呈波动变化的原因主要是宁蒙河段穿越腾格里沙漠、河东沙地、乌兰布和沙漠以及库布齐沙漠,沙漠与河流交互作用,使其具备风沙直接入黄以及支流泥沙入黄的条件;尤其以"十大孔兑"河道上游比降大,河道两岸地表沙物质易蚀性高,从而导致大量泥沙通过洪水过程进入黄河。黄河宁蒙河段的泥沙防治关键在于减少入黄泥沙量,特别是要加强"十大孔兑"地区的水土保持综合防治力度。

Sediment Input and Their Control Along Ningxia- Inner Mongolia Section of Yellow River

The eigenvalues of particle size distribution were analyzed for the sediment of Yellow River from 1950to 2005and the formula addressing mean annual sediment input in any reach of the Yellow River were developed to account the sediment sources inputting into the Ningxia—Inner Mongolia reach of the Yellow River.The results show that a huge amount of sediment was delivered into the Ningxia—Inner Mongolia reach annually from 1950to 2005,and the mean annual sediment input amount varied with time.With data mining and field investigation,we found that the variations were results from the interaction between desert and river as Yellow River flows through the deserts such as Tengger Desert,Hedong sandyland,Ulan Buh Desert and Kubuqi Desert in Ningxia and Inner Mongolia Autonomous Region,where aeolian sediment transportation was a major input source into the river.Furthermore,in the upper reach of"Ten Great Gullies" with great bed gradients,the aeolian sediment covering river banks can be eroded easily by both wind and water and carried into Yellow River by floods.In summary,we think that the key to control channel aggradation of Yellow River is reducing the amount sediment input into the Ningxia—Inner Mongolia reach,which in turn can be achieved through comprehensive prevention measures such as soil and water conservation,ecosystem restoration and engineering measures,which especially should be strengthened in the"Ten Great Gullies"region.