马莲河流域土壤侵蚀特征与模拟

Characteristics and simulation of soil erosion in the Malian River Basin

根据淤地坝拦沙信息与流域输沙量计算马莲河流域土壤侵蚀总量,在系统收集流域降雨、土壤、遥感影像等数据资料的基础上,基于RUSLE模型研究马莲河流域土壤侵蚀分异特征及其变化情况,分析模型计算误差.结果表明,流域土壤侵蚀产沙量总体呈逐年减小的趋势,突变发生在2003年,至2011年达到最小值1.911×10^(7)t,多年均值为6.405×10^(7)t,变化率-4.824×10^(6)t/a.泥沙淤积量自2003年逐年上升,至2010年后占据年土壤侵蚀总量的10%~20%.流域土壤侵蚀等级分布总体上北部地区高于南部地区,多数年份东部地区的土壤侵蚀等级最低,土壤侵蚀模数基本维持在2500 t/(km^(2)·a)以下;2003年后,流域各地区土壤侵蚀等级均有所下降,至2018年绝大多数地区土壤侵蚀模数下降超过200 t/(km^(2)·a);总体RUSLE模型模拟结果良好,多数年份侵蚀产沙量模拟相对误差控制在20%以内.

Total amount of soil erosion in the Malian River Basin was calculated based on the information of silt retention dam and sediment transport in the basin.With the systematic collection of data such as rainfall,soil,and remote sensing images in the basin,the differential characteristics and changes in soil erosion in the Malian River Basin were studied via the RUSLE model,and the model calculation errors analyzed.The results showed that the overall trend of soil erosion and sediment yield in the watershed was decreasing year by year,with a sudden change occurring in 2003 and reaching a minimum value of 1.911×10^(7)t in 2011,with a multi-year average of 6.405×10^(7)t,and an average annual change rate of-4.824×10^(6)t/a.The amount of sediment deposition has been increasing year by year since 2003,accounting for 10%-20%of the total annual soil erosion since 2010.In general,the grade distribution of soil erosion in the northern region is higher than that in the southern region.In most years,the grade of soil erosion in the eastern region was the lowest,and the soil erosion modulus basically remained below 2500 t/(km^(2)·a);after 2003,the soil erosion level in various regions of the watershed has decreased,and by 2018,the soil erosion modulus in the vast majority of regions decreased by over 200 t/(km^(2)·a).The overall simulation results of the RUSLE model are good,and the relative error of erosion and sediment yield simulation in most years is controlled within 20%.