紫色土区小流域侵蚀产沙对水土保持措施的响应

Response of Erosion and Sediment Yield to Soil and Water Conservation Measures in Small Watershed in Purple Soil Region

探讨降雨量与水土保持措施对流域水沙关系的影响,对流域水土流失预报和水土保持效益评价具有十分重要的科学意义,但在紫色土区这方面的研究还相当薄弱。以鹤鸣观小流域Ⅱ号支沟实测降雨径流泥沙数据为基础,分析了水土保持措施对流域径流、泥沙及水沙关系的影响。结果表明:流域治理后期,降雨产流量变化率、降雨产沙量变化率均减小,随着降雨的增多,水土保持措施对径流、产沙的影响效应增强;暴雨强度愈小,降雨量愈少,水土保持径流拦蓄作用愈显著;但降雨量愈大,泥沙拦蓄作用愈显著;流域减水量一般在30%~70%,而减沙量都高于90%,减沙量明显高于减水量;由于水土保持综合治理的作用,1989年后的多年平均径流量较1989年前减少33.11%,多年平均产沙量减少90.50%。

Discussing the effects of precipitation and erosion control practices on the watershed rainfall-runoff-sediment delivery relationships has the important scientific significance on the basin soil erosion prediction and benefit evaluation of soil and water conservation,but the research in purple soil area was very weak.Based on the measured rainfall runoff and sediment data in feeder drainⅡin Hemingguan small watershed,effects of soil and water conservation measures on runoff,sediment and relationship between water and sediment were analyzed.The results showed that after treatment,rate of change of rainfall flow production and sediment yield reduced,and with rainfall increasing,the effect of soil and water conservation measures on runoff and sediment yield enhanced.The smaller the rainfall intensity is,the less precipitation is,and the more significant role of soil and water conservation in reducing runoff is.But the more precipitation is,the more significant role in trapping sediment is.Runoff reduction in small watershed was about 30%~70%,but sediment reduction was above 90%,which suggested that sediment reduction was apparently higher than runoff reduction.Due to the role of comprehensive control of soil and water conservation,the average runoff for many years after 1989 reduced by 33.11%,and the average sediment yield reduced by 90.50% compared to those before 1989.