紫色土坡地径流退水过程与地表糙率试验研究

径流退水过程是降雨产流过程的重要组成部分.通过人工模拟降雨试验,分析了紫色土坡地的退水过程.(1)坡度和雨强对退水流量有显著影响,退水流量随雨强的增加而增加,随坡度的增大而减小.坡度和雨强对退水历时无明显影响.(2)不同地表处理下,退水流量和历时差异显著.顺坡垄作退水过程最短,退水流量最小;裸地退水历时较长,退水流量较大;平作退水历时最长,但是退水流量小于裸地.(3)利用退水曲线法计算了紫色土坡耕地曼宁系数.不同地表处理下曼宁系数的大小为:裸地(0.028)<顺坡垄作(0.065)<平作(0.071).

Runoff Recession and Surface Roughness on Cropland of Purple Soil

Discharge recession process is an important component of rainfall-runoff process.Analysis of recession process of overland flow under simulated rainfall on cropland of purple soil has been carried out.Results show that slope gradient and rainfall intensity have notable effects on recession flux and inverse recession duration.Recession flux increased as rain intensities increased,and reduced as slope became steeper.Recession flux and time varied significantly under different surface treatments.Under downslope cultivation,recession duration is the shortest and recession flux is the least.Recession process holds longer time and greater flux is produced on bare land.For contour cultivation,recession process lasts the longest but recession flux is less than that on the bare land.The Manning's roughness coefficient for the cropland of purple soil is then calculated by using Retention Curve method.In terms of the coefficient,the order of the three treatments are bare land(0.028)< downslope cultivation(0.065)< contour cultivation(0.071).