不同雨强条件下工程措施对坡地产流产沙影响

Effects of Engineering Measures on the Runoff and Sediment Yield in Slope Land Under Different Rainfall Intensities

基于试验站不同坡地措施(坡耕地和坡改梯)2016年和2017年的逐日降水、产流产沙数据,研究不同坡地措施和雨强下产流产沙规律特征,定量揭示坡改梯和坡耕地对产流产沙的影响。结果表明:(1)7月平均雨强I、最大雨强I 30及坡地产流量最大,8月最大雨强I 60与坡地产沙量最大,表明坡地产流产沙高峰期与雨强高峰期一致。(2)春夏两季产流、产沙量与I、I 30和I 60相关性显著(超过95%置信度检验)。其中坡耕地产流产沙量与I、I 30、I 60的相关系数整体高于坡改梯。春夏季坡耕地产沙量分别是坡改梯的3.91,7.85倍。(3)降雨主要集中在I(1~3 mm/h)、I 30(3~29 mm/h)、I 60(2~27 mm/h)之间,且坡地产流产沙量与最大雨强I 30、最大雨强I 60在95%置信度水平呈现显著正相关。当I 30达到29.0 mm/h、I 60达到26.6 mm/h时,坡地产流产沙达到最大,坡耕地产流产沙峰值是坡改梯的2.43,7.52倍以上,并且坡耕地全年产流产沙变异系数总体高于坡改梯,因此坡改梯工程在一定程度上防治了水土流失,使产流产沙变化减小。

Based on the daily precipitation and runoff sediment yield data in 2016 and 2017 under different slope land measures(slope farmland and changing slope to terrace)in the test station,the law characteristics of runoff sediment yield under different slope land measures and rainfall intensities were studied.The impact of changing slope to terrace and slope farmland on runoff and sediment was quantitatively revealed.The results showed that:(1)In July,the average rainfall intensity I,the maximum rainfall intensity I 30 and the slope land runoff were the largest,and in August,the maximum rainfall intensity I 60 and the slope land sediment yield were the largest,indicating that the peak of runoff and sediment was the same as the peak of rainfall intensities.(2)The correlations between runoff and sediment yield in spring and summer and I,I 30 and I 60 were significant(more than 95%confidence test).The correlation coefficients in slope land were higher than those in changing slope to terrace land.In spring and summer,the sediment yields in slope land were 3.91 and 7.85 times of those in changing slope to terrace land.(3)The rainfall was mainly concentrated in I:1~3 mm/h,I 30:3~29 mm/h,I 60:2~27 mm/h,and the runoff and sediment yield in slope land was positively correlated with the maximum rainfall intensity I 30 and I 60 at 95%confidence level.When I 30 reached 29.0 mm/h,I 60 reached 26.6 mm/h,the runoff and sediment yield in slope land reached the maximum.The peak values of runoff and sediment yield in slope land were 2.43,7.52 times higher than those in changing slope to terrace land.The variation coefficients of runoff and sediment yield in the whole year were higher than those in changing slope to terrace land.Thus,changing slope land to terrace could prevent soil erosion to a certain extent,and reduce the variation of runoff and sediment yield.