黄河流域窟野河入黄水沙锐减成因分析

Analysis on the cause of sharp decrease of runoff and sediment from Kuye River in Loess Plateau

2000年以来,窟野河入黄水沙量急剧减少,减幅分别达67%和96%。本文分析了该流域的降雨-产水(沙)关系变化、坝库拦沙量、生产生活用水、植被和采煤对产水产沙的影响,结果表明,1980—2011年,降雨一直是窟野河水沙偏少的重要因素,其中1997—2011年降雨对减水减沙的贡献分别为25.3%和51.2%,但2012年以来雨量和雨强均偏大、实为增水增沙因素。植被改善是近20多年窟野河沙量锐减的主要下垫面因素,其中1997—2011年和2012—2019年对下垫面减沙量的贡献分别为66.7%和89.1%,并使流域产水能力降低约37%和58%。大规模采煤使流域水循环路径变化、汇流时间延长、洪水坦化,其中1997—2011年急剧增加的采煤活动使入黄水量减少1.18亿m^(3)/a、每采1吨煤约损失1吨水;2012年以来,矿井封存水的缓慢溢出使入黄径流增加。包括煤矿生产生活用水在内的人类用水随经济发展而增加,近20年对径流减少的贡献率近20%。坝库拦沙也是窟野河沙量减少的重要因素,但其贡献率不断降低,其中2012年以来不足1.2%。若植被不退化,预计未来入黄水沙量将持续近几年的态势。

The water and sediment quantity of the Kuye River have sharply decreased to 67%and 96%separately since 2000.The Possible factors were investigated and studied,such as the change of the relationship between rain and water or sediment,sediment quantity intercepted by dams,water used by people,the influence of the vegetation restoration and coal mining.It was revealed that poor rain has been the major reason accounting for the water-sediment decrease from 1980 to 2011,and its contribution rate from 1997 to 2011 were 25.3%on water and 51.2%on sediment.But rain have become a positive factor because of the more rainfall quantity and higher intensity since 2012.Vegetation restoration has been the main underlying factor accounting for water-sediment decrease,and its contribution were separately 66.7%from 1997 to 2011 and 89.1%from 2012 to 2019,and also reduced the runoff production ability by 37%and 58%.The extensively coal mining have caused the water cycle path change,the runoff confluence time delay and the flood process flatten.During 1997 to 2011,the greatly increasing coal mining caused the run⁃off into Yellow River decreased by 0.118 billion ton per year averagely,which means about 1 ton water loss by each 1 ton coal production.But since 2012,the mine water confluence have even caused the run⁃off increase gradually.The water consumption by human activity including mining production and others has increased with the energy economy development,and its contribution rate to the river’s runoff decrease was nearly 20%during recent 20 years.The Dam interception also was an important factor accounting for the sediment decrease,but its contribution rate has become less and less,even less than 1.2%since 2012.If the vegetation could keep its present degree,the future runoff and sediment into Yellow River would be maintained at its present level。