Hu Ke, Chen Hongsong, Nie Yunpeng, Wang Kelin
1] Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China [2] Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang, Guangxi 547100, China [3] Graduate University of Chinese Academy of Sciences, Beijing, 100049.
1] Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, 410125, China [2] Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang, Guangxi 547100, China.
Sci Rep. 2015 May 11;5:10215. doi: 10.1038/srep10215.
Soil and epikarst play an important role in the hydrological cycle in karst regions. This paper focuses on investigating the seasonal recharge and mean residence time (MRT) of soil water and epikarst water in a small karst catchment of southwest China. The deuterium contents in precipitation, creek, soil baseflow (direct recharge of the saturated soil water to the stream), epikarst spring, and soil waters were monitored weekly for two years, and MRT was calculated by an exponential model (EM) and a dispersion model (DM). The obvious seasonal variation of deuterium in rainfall was buffered in epikarst water, indicating sufficient water mixing. Soil baseflow contained less rainy-season rainwater than epikarst spring discharge, reflecting the retarded effect of soil thickness on rainwater recharge. MRTs of all water bodies were 41-71 weeks, and soils in the depression extended those of shallow groundwater. This demonstrated that the deep soil layer played an important role in karst hydrological processes in the study catchment. The creek was recharged mostly by rainfall through epikarst, indicating its crucial role in water circulation. These results showed epikarst had a strong water-holding capacity and also delayed water contact time with dolomite.
土壤和表层岩溶带在喀斯特地区的水文循环中起着重要作用。本文着重研究中国西南部一个小型喀斯特流域土壤水和表层岩溶带水的季节性补给及平均停留时间（MRT）。连续两年每周监测降水、小溪、土壤基流（饱和土壤水对溪流的直接补给）、表层岩溶泉和土壤水的氘含量，并通过指数模型（EM）和弥散模型（DM）计算MRT。降雨中氘的明显季节变化在表层岩溶泉水中得到缓冲，表明有充分的水体混合。土壤基流中雨季雨水含量低于表层岩溶泉流量，反映了土壤厚度对雨水补给的阻滞作用。所有水体的MRT为41 - 71周，洼地土壤延长了浅层地下水的MRT。这表明深层土壤层在研究流域的喀斯特水文过程中起重要作用。小溪主要通过表层岩溶带接受降雨补给，表明其在水循环中的关键作用。这些结果表明表层岩溶带有很强的持水能力，并且延长了水与白云岩的接触时间。
