黔北浒洋水侵蚀性次降雨对地表径流产沙的影响

为研究黔北小流域侵蚀性降雨与产沙的关系, 以遵义浒洋水水土保持监测站2009—2012年降雨实测资料为基础, 在4个径流小区各28场降雨的降雨量、降雨强度、最大30 min雨强、降雨侵蚀模数等数据统计的基础上, 采用次降雨侵蚀力、覆盖度的回归模型及多元非线性回归方法, 分析浒洋水小流域的次降雨径流侵蚀产沙规律。结果表明:流域内5-7月份总径流量、总产沙量分别占全年总量的64.05%和62.62%。当次降雨侵蚀力 < 20, 降雨侵蚀模数与降雨侵蚀力呈幂函数正相关关系, 降雨侵蚀模数与覆盖度呈二次函数负相关关系; 当降雨侵蚀力>20, 降雨侵蚀模数与降雨侵蚀力呈一次函数正相关关系, 降雨侵蚀模数与覆盖度呈幂函数负相关关系。通过二元非线性回归, 建立并验证次降雨侵蚀力、覆盖度与降雨侵蚀模数之间的适用公式。

Effects of Erosive Single Rainfall on Surface Runoff Sediment Yield in Huyangshui in Northern Region of Guizhou Province

The relationship between sediment yield and erosive rainfall was studied based on the observed rainfall data of Huyangshui water and soil conservation monitoring stations in Zunyi from 2009 to 2012.The rainfall runoff erosion and sediment yield of small watershed in Huyangshui were analyzed using single rainfall erosivity, and the coverage of the optimal calculation model and multivariate nonlinear regression method with the data statistics of 4 runoff plots in the 28 times rainfall including rainfall, rainfall intensity, maximum 30 minutes rainfall intensity and time of rainfall erosion modulus.The results showed that the output of total runoff and sediment accounted for 64.05% and 62.62% respectively of the annual total from May to July in the basin.When rainfall erosivity was less than 20, the rainfall erosion modulus and rainfall erosivity was a positive correlation in power function, the rainfall erosion modulus and coverage was a negative correlation in quadratic function.When rainfall erosivity was more than 20, rainfall erosion modulus and the erosivity was positively in a function, the rainfall erosion modulus and coverage was negatively related to the power function relationship.The applicable formula among single rainfall erosivity, coverage and erosion modulus was established and verified through the binary nonlinear regression.