延河流域水土保持对径流泥沙的影响

 采用Mann-Kendall统计检验方法和Pettitt系列显著性突变点的无参数识别方法分析延河流域径流和泥沙演变趋势及突变点,基于流量历时曲线分析延河流域突变点前后径流和泥沙变化特征,研究了水土保持措施对流域径流和泥沙的影响。结果表明:延河流域径流和输沙量均呈减少趋势,输沙量在1971和1996年有2个显著性的突变点,对于黄土高原丘陵沟壑区,水土保持措施减少河川径流量和输沙量。随着突变点后期水土保持措施力度的加大,水土保持措施拦蓄径流和泥沙的作用逐渐增强。水土保持措施使径流高流量部分减少,常流量和低流量部分增加,表明水土保持措施可削减汛期流量,增补枯季流量。突变点后期输沙量较之变化前期整体呈减少趋势。研究结果可为黄土高原丘陵沟壑区的水土保持和水资源管理工作提供一定参考。

Impact of soil and water conservation on runoff and sediment in Yanhe River Basin

The nonparametric Mann-Kendall test and the Pettitt test are used to identify evolution trends and change points in the runoff and sediment records.The Flow Duration Curve(FDC) is also used to assess the runoff and sediment response to soil and water conservation of the pre-change and post-change periods in the Yanhe River Basin in this study.The results show that the change points in sediment occurred in 1971 and 1996.The soil and water conservation measures can obviously decrease runoff and sediment,reduce the flood-season runoff and increase dry-season runoff.Compared to pre-change periods,runoff regime of Yanhe River Basin shows reduction in high flows.This paper provides a scientific basis for future water resources management and evaluation of soil and water conservation benefits for hilly and gully region of Loess Plateau.