中文摘要：

20世纪60年代以来，黄河中游地区一系列大规模人类生产活动如引水灌溉、水土保持等，使得黄河中下游的径流情势在过去的几十年里经历了较大的变化，造成流域水土流失、生态恶化和经济损失严重。本文以黄河中游的岔巴沟流域为例，研究了1959～2000年黄河中游地区人类活动对径流情势的影响。结果表明：流域径流在1978年受到水土保持活动的显著干扰，年径流量减少了30％以上，且径流年际、年内变化均有所减小。此外，流域径流情势随淤地坝有起有落的发展过程出现了一系列相应的变化。

英文摘要：

The Yellow River has experienced significant changes in hydrological regime in recent 40 years. These changes have serious implications for water and soil losses, ecologic crisis, and economic losses. The changes of of runoff regime in the Chahagou Basin during the period from 1956 to 1999 have been studied. The results indicate that a significant change point of runoffappeared in 1978, and the change mainly due to soilwater conservation measures. The average annual runoffreduced by 30% was compared with that in the period before 1978. The reduction of the annual runoffwas associated with the decreased interannual and intraannual variability in runoff. In addition, the hydrological regime of the basin changed consistently with the up and down progress of sediment-trapping dams.