黄河水沙空间分布及其变化过程研究

本文对不同时期黄河水沙的空间分布及其变化过程进行了系统分析,研究结果表明,1950～2005年黄河年平均总水量约为593.5亿m3(其中包括水土保持减水量、干支流引水耗水量及河口入海水量),年平均总沙量约为17.9亿t(其中包括水土保持减沙量、水库拦沙量、引水引沙量、放淤固堤沙量、河道冲淤量及河口人海沙量),不同时期黄河水沙总量变化很大,但黄河总水沙量比基本稳定为0.03t/m3.1986年以来黄河下游来水来沙量减少的主要原因,一是上中游耗水减沙量增多,1986～1998年平均上中游水土保持减水和工农业引水等耗水量达213亿m3,水土保持减沙、水库拦沙、引水引沙和河道冲淤等沙量合计达8.57亿t,已分别占上中游总水沙量的45%和53%,二是自然气候条件改变,引起上中游1986～1998年平均总水量比1973～1985年减少约136亿m3,而上中游年平均总沙量只减少约0.7亿t,导致水少沙多的局面加重.由于自然条件的变化和人类活动的影响,黄河水沙空间分布更趋不合理,表现为主河槽萎缩、"二级悬河"加剧、河口退蚀等,引起小水大灾和生态恶化,防洪形势更为严峻,应通过水沙联合优化配置和泥沙资源化利用治理黄河的水沙灾害.

China Institute of Water Resources and Hydropower Research, Beijing 10004, China

The spatial distribution and its variation process of sedimentation in the Yellow River in various periods were systematically analyzed. It is found that in the period from 1950 to 2005, the annual average total water volume of the river is 59.35 billion m3 and total sedimentation is 1.79 billiont respectively, the conrresponding sedimentation generation rate is 0.03t/m3. One reason causing the decrease of water and sedimentation in the lower reaches of Yellow River since 1986 is the increase of water consumption in the upper and middle reaches of the river due to mankind activity. Another reason is the changes of climate. Because of the decrease of precipitation the incoming annual average total water volume of upper and middle reaches of the river decreased by 13.6 billion m3, but the corresponding incoming sedimentation is merely reduced by 0.07 billion t. This inappropriate composition of water and sedimentation results in the shrinkage of main channel, deterioration of ecoenvironment and more water disaster. For changing this situation the optimal joint deployment of water and sediment and reasonable utilization of sediment resources are important measures to be adopted.