大渡河流域干旱河谷区坡面侵蚀产沙与水动力学特征研究  

Study on Characteristics of Slope Erosion Sediment Production and Hydrodynamics in Arid Valley Area of Dadu River Basin

作　　者：何周窈 何淑勤[1,2,3] 逯传琦 郑子成 HE Zhou-yao;HE Shu-qin;LU Chuan-qi;ZHENG Zi-cheng(College of Forestry,Sichuan Agricultural University,Chengdu 611130,China;National Forestry and GrasslandAdministration Key Laboratory of Forest Resources Conservation and Ecological,Chengdu 611130,China;Key Lab of Soil and Water Conservation and Desertification Combating,Sichuan Agricultural University,Chengdu 611130,China;College of Resources,Sichuan Agricultural University,Chengdu 611130,China)

机构地区：[1]四川农业大学林学院,四川成都611130 [2]长江上游森林资源保育与生态安全国家林业和草原局重点实验室,四川成都611130 [3]四川农业大学水土保持与荒漠化防治重点实验室,四川成都611130 [4]四川农业大学资源学院,四川成都611130

出　　处：《长江流域资源与环境》2023年第4期832-841,共10页Resources and Environment in the Yangtze Basin

基　　金：四川省重点研发项目(2019YFS0463)。

摘　　要：为探究干旱河谷区强降水条件下坡耕地水流特性的变化情况,以汉源县典型坡耕地土壤为研究对象,采用人工模拟降雨实验,探究了不同降雨强度(1.0、1.5、2.0 mm/min)对不同坡度(10°、15°、20°)的横垄及平作坡面的产沙率和水动力学参数的影响。结果表明:(1)随着降雨时长的增加,各坡面的侵蚀产沙率先增后减;阻力系数则逐渐减小后趋于稳定;径流剪切力和单位径流功率呈增加趋势,后维持相对稳定的状态。(2)随着降雨强度的增加,不同坡度的横垄坡面产沙率增加了4.43~38.96倍,径流剪切力增加了0.49~3.40倍,单位径流功率增加了0.64~1.50倍;平作坡面产沙率增加了1.46~1.81倍,径流剪切力增加了0.94~1.30倍,单位径流功率增加了0.11~0.52倍。而阻力系数随着降雨强度的增加而减小,但不同坡度坡面间的阻力系数未表现出明显的规律。(3)不同实验条件下,横垄坡面的侵蚀产沙率和径流剪切力总体低于平作坡面。而二者间的阻力系数和单位径流功率虽差值较大,但无明显规律。(4)降雨强度的增加导致各坡面的径流流态从“层流-缓流区”(Re<500,Fr<1)转变为“紊流-缓流区”(Re>500,Fr<1)。综上所述,在强降水条件下,不同坡度的坡耕地均可通过横垄措施有效调控水沙过程从而达到良好的减沙效益。The purpose of this study was to explore the change of flow characteristics of sloping farmland under heavy rainfall conditions in arid valley.In this study,Hanyuan County as the research area,using artificial simulation precipitation experiment.Three different precipitations(1.0,1.5 and 2.0 mm/min)and three different slopes(10°,15°and 20°)were set in the experiment.The effects of different precipitation on hydraulic properties on cross-ridge slope and flat slope were investigated.The results showed that with the increase of rainfall duration,the erosion sediment yield of all slopes increased firstly and then decreased.The resistance coefficient gradually decreases and then tends to be stable.The runoff shear force and unit runoff power increase gradually with time and then maintain a relatively stable state.With the increase of rainfall,sediment yield,runoff shear force and unit runoff power of cross-ridge slope increased by 4.43~38.96 times,0.49~3.40 times and 0.64~1.50 times respectively.On the flat slope,the sediment yield increased by 1.46~1.81 times,the runoff shear force increased by 0.94~1.30 times,and the unit runoff power increased by 0.11~0.52 times.Under different experimental conditions,the erosion sediment yield rate and runoff shear force of cross-ridge slope were significantly lower than those of flat slope,and the resistance coefficient and unit runoff power of cross-ridge slope and flat slope were different,but there was no obvious regularity.As precipitation increased from 1.0 mm/min to 2.0 mm/min,the runoff pattern on all slopes changed from"laminar slow-flow zone"(Re<500,Fr<1)to"turbulent slow-flow zone"(Re>500,Fr<1).In summary,under the condition of heavy precipitation,hilly croplands with different slopes can effectively control the process of water and sediment by cross ridge measures,thus achieving good sediment reduction benefits.

关 键 词：干旱河谷 强降水 横坡垄作 产沙率 水流特性 

分 类 号：S157.1[农业科学—土壤学]