吕二沟小流域水土保持措施对径流和侵蚀产沙的影响

以甘肃天水吕二沟流域22年实测水文泥沙数据为基础，从降水～侵蚀产沙、径流～产沙关系入手，统计分析了小流域水土保持措施对径流和侵蚀产沙的影响。结果表明：小流域径流和侵蚀产沙在年内的分布与降水的季节分配和植被生长发育期有关；径流和侵蚀产沙的年际变化是随流域水土保持措施全面实施和小流域林草植被面积的增加，流域径流量和侵蚀产沙量逐渐减少。从单次降水～径流、降水～侵蚀产沙关系曲线来看，小流域水土保持措施发挥着明显的减水、减沙效益，为流域的综合治理、水土资源的合理开发利用提供科学依据。

Effects of water-soil conservation measures on runoff and soil erosion induced sediment yield in Lüergou Watershed

Based on the observed hydrologic and sediment data within the period from 1982 to 2004 of Luergou Watershed located in Tianshui, Ganshu Province, the effects from the water-soil conservation measures on the runoff and soil erosion induced sediment yield are statistically analyzed herein from the relationships of both the precipitation soil erosion induced sediment yield and the runoff sediment yield. The study reveals that the distribution of runoff and soil erosion induced sediment yield within a year varies with the seasonal distribution of precipitation and the growth period of vegetation. The annual variation of runoff and erosion induced sediment yield gradually decreased along with the development of soil and water conservation work and the increase of forest and grass vegetation. On the basis of the relationship between the precipitation runoff and the relationship between precipitati- on and erosion induced sediment yield, it is found that obvious benefits of sediment and runoff reduction are obtained from the water-soil conservation measures for small watersheds, which provides a scientific basis for comprehensive development of watershed and reasonable development and utilization of land-water resources.