EUROSEM模型对晋西黄绵土坡面侵蚀过程的模拟应用

晋西黄绵土坡面因其土壤、降雨等条件极易造成严重水土流失,本文基于不同坡长(2、3、4 m)与雨强(60、90、120 mm/h)组合方式下的野外人工模拟降雨试验,应用EUROSEM模型对坡面径流侵蚀过程及产流产沙总量进行模拟,通过对比分析模拟值与实测值,评价该模型对晋西黄绵土坡面土壤侵蚀过程的模拟效果及在该区的适用性。结果表明:坡长、雨强与产流产沙总量均为正相关关系,雨强对其影响较坡长大,但二者之间具有制约作用,偏相关分析显示当二者单独作用于产流产沙总量时,相关性均增大,且坡长与产流产沙总量的相关性明显较共同作用时增大;模型模拟产流率峰值出现时间与实测值稍有偏差,而模拟产沙率峰值首次出现时间较实测值提前了约5 min;当雨强大于60 mm/h,坡长由3 m延长至4 m时,产流产沙总量实测增量较2 m延长至3 m减小,而4 m坡长条件下,产流产沙总量模拟值几乎均大于实测值。总体而言,EUROSEM模型在晋西黄绵土坡面上有较好的适用性,模型对产流过程的模拟较产沙过程更为准确,产流产沙总量的模型模拟值与实测值间相对误差RE在许可范围之内,效率系数ME分别为0.978、0.974。

Simulation of erosion process on loessal slope in western Shanxi by using EUROSEM

Loessal slope in Western Shanxi can cause severe soil erosion due to its typical soil and rainfall conditions. Based on the different combinations of slope lengths (2, 3, 4m) and artificial rainfall intensi- ties (60, 90, 120mm/h) in the field, this study simulated the runoff and sediment yield processes by us- ing ERUOSEM. Likewise, the simulated results and experimental measured values were compared to evalu- ate the simulation effectiveness of the EUROSEM and its applicability in study area. The results show that both of slope length and rainfall intensity have positive relationships with total runoff volume and sediment yield,furthermore,rainfall intensity has greater effect than the slope length,but they are restricted mutual- ly. Whereas, partial correlation analysis indicates that both rainfall intensity and slope length have greater correlation coefficient when act on runoff and sediment yield separately. There is a slight deviation between the peak time of simulated runoff rate and the measured value, and the first time of the peak sediment transport rate is about 5 minutes earlier than the actual one. When rainfall intensity greater than 60mm/h and the slope length extends from 3m to 4m, the increments of runoff and sediment yield decrease than that from 2m to 3m. In addition, when the slope length is 4m, the simulated values of total runoff and sediment yield are almost all greater than the measured values. In summary, EUROSEM is well applied to loessal soil in Western Shanxi and is more accurate on simulating runoff process than on sediment yield process. The relative error RE between runoff and sediment yield simulated and the measured values is with- in the allowable range,and ME are 0.978 and 0.974,respectively.