典型喀斯特小流域水文水化学过程对旱季暴雨的响应  

Hydrochemical Responses of Stormflow to Extreme Rainfall during Dry Season in a Typical Karst Catchment of Northwest Guangxi Province,China

作　　者：刘春[1,2,3] 杨静[1,2,4] 聂云鹏[1,2] 陈洪松[1,2] 付智勇[1,2] 

机构地区：[1]中国科学院亚热带农业生态研究所,亚热带农业生态过程重点实验室,长沙410125 [2]中国科学院环江喀斯特生态系统观测研究站,广西环江547100 [3]湖南师范大学资源与环境科学学院,长沙410081 [4]中国科学院大学,北京100049

出　　处：《地球与环境》2015年第4期386-394,共9页Earth and Environment

基　　金：973计划项目(2015CB452703);中国科学院西部行动计划项目(KZCX2-XB3-10);国家自然科学基金项目(41301300);中国科学院2012年度“西部之光”人才培养计划“西部博士资助项目”;湖南省研究生科研创新项目(CX2014B226)

摘　　要：通过定位监测和样品跟踪采集,在旱季对喀斯特小流域连续20天无前期降雨的一场暴雨(累计降雨量64mm)水文水化学过程进行了动态监测,并分析了相关的影响因素。结果表明,小降雨事件(8.5mm)未能引起溪流水位、电导率及温度的明显变化,而当累计降雨量达到35.5mm后溪流水开始响应。此后,溪流水文水化学参数对降雨快速响应,除硝态氮外,电导率(EC)、δ18 O、Ca2+迅速降至最低值,雨水稀释作用对其水化学变化起主要作用。通过对溪流新旧水比例进行划分发现,降雨前期和后期,溪流以旧水补给为主,而在水位快速上涨阶段,新水比例达到34%左右。两次降雨过程中,在溪流水水位升高的情况下,水体中硝态氮浓度仍然表现出高于雨前浓度的趋势。该研究为该区旱季小流域水资源利用和污染物防治方面提供了一定理论依据。Based on in situ observation and tracing sampling, hydrochemical process in a karst small watershed during a rainstorm （64 mm） after 20-d drought in dry season were studied. Furthermore, the influencing factors were analyzed. Results show that the responses of water stage, electrical conductivity, temperature and pH were not obvious during the first rainfall event （8.5 mm）. The stream did not response to the rainfall until the rainfall amount reached 35, 5 mm. After that, all hydrochemical indexes, except for the nitrate nitrogen, began to rapidly change, Conductivity, δ18 O, and Ca2＋ quickly dropped to the lowest values because of the dilution effect. The stream was mainly recharged by the supply of old water during the early and late rainfalls. However, the proportion of new water was up to 34% during the rapidly rising of the water stage. In the two rainfalls, although the water stage increased, the concentration of nitrate nitrogen （NO3--N） was still higher than its value before the rainfall event. The research provides necessary information for the small watershed water resources utilization and contaminant controlling.

关 键 词：响应 同位素 降雨 小流域 喀斯特 

分 类 号：P592[天文地球—地球化学]