摘要
表层岩溶带是喀斯特关键带的核心区域,具有重要的水文调蓄功能,但岩溶发育程度对表层岩溶带水文特征的影响还不明晰。本研究采用地球物理勘探和水文地质钻探技术,结合水分和水位动态监测,量化坡地岩溶发育和水文特征,解析土壤-表层岩溶带对降雨的响应规律。结果表明:地球物理勘探可以较好地运用到岩溶区关键带结构的探测,坡地土壤和表层岩溶带厚度平均值分别小于0.63和2.60 m。岩溶化程度强的坡地视电阻率较高,节理裂隙发育且渗透性强(0.73 m·d^(-1));表层岩溶带对降雨的调节能力更强,表现为土壤水分变化具有较大的降雨阈值(>20.50 mm·d^(-1))和由降雨量主导的水位变化过程。岩溶发育程度弱的坡地视电阻率低且渗透性弱(0.07 m·d^(-1));水分和水位变化对降雨的响应迅速,同时,局部(240~300 cm深度)发育岩溶管道,渗透系数达432 m·d^(-1),在极端降雨事件(暴雨/大暴雨)过程中观察到明显的优先流特征,相邻洼地遭受洪涝的风险更大。该结果有助于进一步深化西南喀斯特地区水资源调控、管理及生态水文研究。
Epikarst is the core area of karst critical zone,with important hydrologic regulation and storage function.However,the effects of karst development degree on hydrologic characteristics of epikasrt is still unclear.We used geophysical exploration and hydrogeological techniques,combined with the dynamic monitoring of moisture and water levels,to quantify the karst development degrees and their hydrologic characteristics on slope lands.We analyzed the responses of soil-epikarst systems to rainfall.Results showed that geophysical exploration technology could be well applied to the detection of surface-subsurface structures in the karst areas.The average thickness of soil and surface karst zone on the slope was less than 0.63 m and 2.60 m,respectively.The slopes of strong-karstification characterized by high apparent resistivity,well-developed joint fractures,and strong permeability(0.73 m·d^(-1)).Such a result indicated that epikarst could regulate precipitation.The responses of soil moisture had a larger rainfall threshold(>20.50 mm·d^(-1))and the water level was determined by rainfall amount.In contrast,the slope with weak-karstification had low apparent resistivity and weak permeability(0.07 m·d^(-1)).Moisture and water level were sensitive to rainfall.Karst channels were developed locally at 240-300 cm with a permeability coefficient of up to 432 mm·d^(-1).Obvious preferential flow was observed in extreme rainfall events on this slope,which could induce flood disaster in the adjacent depression.Our results would provide scientific basis for further research on water resources regulation,management,and eco-hydrology in karst areas of southwest China.
作者
张君
付智勇
陈洪松
连晋姣
覃常
ZHANG Jun;FU Zhi-yong;CHEN Hong-song;LIAN Jin-jiao;QIN Chang(Key Laboratory of Agro-ecological Processes in Subtropical Region,Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha 410125,China;Huangjiang Observation and Research Station of Karst Ecosystem,Chinese Academy of Sciences,Huangjiang 547100,Guangxi,China;University of the Chinese Academy of Sciences,Beijing 100049,China;Guangxi Hydrogeology and Engineering Geology Institute,Liuzhou 545006,Guangxi,China)
出处
《应用生态学报》
CAS
CSCD
北大核心
2021年第6期2107-2118,共12页
Chinese Journal of Applied Ecology
基金
国家自然科学基金重点项目(41930866)
国家自然科学基金项目(41971048,41701044)资助
广西自然科学基金创新研究团队项目(2018GXNSFGA281003)。
关键词
喀斯特关键带
地球物理勘探
表层岩溶带厚度
渗透系数
水分变化
水位变化
karst critical zone
geophysical exploration
thickness of epikarst
permeability coefficient
water dynamic
groundwater level dynamic
