基于人工降雨试验的淮北地区产流产沙差异性研究

Difference of runoff and sediment yield under various experimental conditions for the Huaibei area based on artificial rainfall simulations

  • 摘要: 针对淮北地区水土流失问题,利用野外人工模拟降雨试验,分析了不同雨强(40 mm/h、60 mm/h和80 mm/h)和坡度(5°、10°和15°)条件下砂姜黑土和黄潮土产流产沙差异。结果表明:砂姜黑土初始产流时间长,产流总量小。坡面出现细沟时,砂姜黑土初始含沙量随时间变化有减小趋势,最终趋于稳定,而黄潮土含沙量呈波动变化;60 mm/h、80 mm/h雨强10°坡砂姜黑土产沙总量大于黄潮土,其他情况黄潮土产沙总量大于砂姜黑土,黄潮土土壤侵蚀严重。砂姜黑土表面细沟发育密度大,主要在坡面中下部,为相互连通的树枝状结构,而黄潮土表面细沟发育密度小,形成沟壑。两种土壤产流总量、产沙总量与坡度、雨强分别呈多元线性函数、多元幂函数关系,雨强对坡面产流产沙总量的影响大于坡度。

     

    Abstract: Aiming at the problems of soil and water losing in the Huaibei area,the difference of runoff and sediment yielding from the Lime Concretion Black soil (LCBS) slope and the Fluvo-aquic Yellow soil (FYS) slope with gradients of 5°,10°,15° under different rainfall intensities (40 mm/h,60 mm/h,80 mm/h) was experimentally investigated. The results show that the initial runoff yielding time from the LCBS slope is longer than that from the FYS slope while the total runoff yield is relatively smaller for the LCBS slope. The initial flow sediment concentration from LCBS slope tends to decrease once slope rills appearing and eventually to a stable level. However,the flow sediment concentration from the FYS slope exhibits a fluctuating change. Sediment yield from the LCBS slope is less than that from the FYS slope under the various experimental conditions with exception of the combining situations of slope gradient 10° and rainfall intensity of 60 mm/h or 80 mm/h. The rills were well developed to an interconnected dendritic structure on the LCBS slope surface with a higher density rills occurring in the middle and lower part of the slope. Relatively,the rill density on the FYS slope surface is smaller. The runoff,sediment yield highly correlated to the slope gradient,rain intensity with multivariate linear and multivariate power relationships respectively for the both soil type slopes. The rainfall intensity gains a higher effect on runoff and sediment yield than slope gradient does.

     

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