Subsurface flow in a soil-mantled subtropical dolomite karst slope: A field rainfall simulation study
Subsurface flow in a soil-mantled subtropical dolomite karst slope: A field rainfall simulation study
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土幔亚热带白云岩喀斯特斜坡的地下流：野外降雨模拟研究
DOI：
10.1016/j.geomorph.2015.08.012
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发表时间：
2015-12-01
期刊：
影响因子：
3.9
通讯作者：
Wang, K. L.
中科院分区：
文献类型：
--
作者：
Fu, Z. Y.;Chen, H. S.;Wang, K. L.
在喀斯特地区，土壤与表层岩溶共同演化形成复杂的结构，但其耦合结构对水文过程的影响尚不清楚。以西南湿润亚热带座舱型喀斯特地区为研究对象，从土壤-表层喀斯特综合系统的角度研究了样地尺度下的地下水流特征。在表层岩溶下边界开挖一条沟槽，收集5个不同土层厚度断面的个别地下水流。在不同初始湿度条件（干湿）和平均降雨强度（高114 mm h（-1）和低46 mm h-1）下进行了4次野外降雨模拟试验。土壤-表层岩溶系统的特征是浅土层覆盖高度不规则的表层岩溶，入渗速率接近稳定，约为35 mm h-1。地下流动主要沿土壤-表层岩溶界面流动，以优先流动为主。地下水流线表现出较强的空间变异性，且具有较高的稳态系数（强降水和弱降水事件的稳态系数分别为0.52和036）。不规则的表层与高垂直排水能力相结合，导致地下流的高阈值降雨深度：初始湿润和干燥条件下分别为67 mm和263 mm。上述结果表明，不规则且具有渗透性的土壤-表层岩溶界面是土壤-表层岩溶结构的重要组成部分，在岩溶区水文建模中应予以考虑。(C) 2015 Elsevier B.V.版权所有
Soil and epikarst co-evolve resulting in complex structures, but their coupled structural effects on hydrological processes are poorly understood in karst regions. This study examined the plot-scale subsurface flow characteristics from an integrated soil-epikarst system perspective in a humid subtropical cockpit karst region of Southwest China. A trench was excavated to the epikarst lower boundary for collecting individual subsurface flows in five sections with different soil thicknesses. Four field rainfall simulation experiments were carried out under different initial moisture conditions (dry and wet) and rainfall intensities (114 mm h(-1) (high) and 46 mm h-1 (low) on average). The soil-epikarst system was characterized by shallow soil overlaying a highly irregular epikarst surface with a near-steady infiltration rate of about 35 mm h-1. The subsurface flows occurred mainly along the soil-epikarst interface and were dominated by preferential flow. The subsurface flow hydrographs showed strong spatial variability and had high steady-state coefficients (0.52 and 036 for high and low rainfall intensity events). Irregular epikarst surface combining with high vertical drainage capacity resulted in high threshold rainfall depths for subsurface flows: 67 mm and 263 mm for initial wet and dry conditions, respectively. The above results evidenced that the irregular and permeable soil-epikarst interface was a crucial component of soil-epikarst architecture and consequently should be taken into account in the hydrological modeling for karst regions. (C) 2015 Elsevier B.V. All rights reserved.