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利用黄土高原典型流域延河流域水文和退耕还林数据,分析退耕还林还草工程对流域水土保持功能的影响,探讨了近30年来流域水文变化过程及水文指标与退耕还林还草指标的关系。研究结果表明:30年来流域降水量减少趋势不显著,径流量和输沙量均成显著下降趋势。将流域径流量和输沙量变化序列分为前期(1980-2002年)和退耕还林还草影响期(2003-2010年)两个阶段进行比较分析,退耕还林还草影响了降水径流关系,削弱了流域产流能力,退耕还林还草影响期流域产沙动力系数下降。累计退耕还林还草面积与径流系数和含沙量均呈负相关,其中径流系数与之负相关性显著。
Based on the data of hydrology and returning cropland to forest in the Yanhe River Basin, a typical watershed in the Loess Plateau, the impacts of the project of returning farmland to forest to grassland on the function of soil and water conservation in the basin are analyzed. The hydrological index, relationship. The results show that the trend of decrease of precipitation in the basin is not significant in 30 years, both the runoff and the sediment discharge have a significant downward trend. The series of runoff and sediment discharge in the basin were divided into two periods: pre-stage (1980-2002) and the impact period of conversion of farmland to forestland and forestry (2003-2010). The conversion of farmland to forestland and grassland affected the relationship between precipitation and runoff , Weakened the flowability of the basin and the dynamic coefficient of sediment yield in the basin during the period of conversion of farmland to forestry and grassland decreased. The cumulative area of returning farmland to forestry and grassland has a negative correlation with runoff coefficient and sediment concentration, of which runoff coefficient has a significant negative correlation.