Water flow characteristics of Maocun underground river basin based on environmental isotopes
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摘要:
岩溶水文特征是岩溶区生态环境可持续发展的关键驱动力。文章利用环境同位素示踪剂反馈的水动力过程，解译毛村地下河流域的水流特征。其流域内水体δD和δ18O范围均位于大气降水δD和δ18O的范围内，大气降水是流域主要的补给来源；基于δ13CDIC利用质量守恒定律计算岩溶水体中DIC来源于碳酸盐岩溶解的平均值为52.13‰，可揭示相关的水—碳酸盐岩相互作用历程；流域内岩溶水点222Rn和EC值对大气降水的响应特征表明降水的蓄积作用可驱动深层岩溶裂隙水运移，且具有较强的稀释作用；基于222Rn的衰变特征，计算6月份地下河管道有效水流速度为2 427.49 m·d−1；西南岩溶地下河水流与地表水流相似，且对降水响应敏感。综合毛村地下河流域的水文地质条件及其水文点SI、222Rn、δ13CDIC和δ18O间的相关关系，环境同位素可更好地示踪岩溶裂隙水流特征，揭示岩溶含水系统的空间结构特征及水流路径。水化学环境天然示踪剂可提供有关岩溶含水系统的重要信息，对水动力学方法具有重要的补充作用。
Abstract:Underground river basins in peak-cluster depressions are main water supply sources of villages in Guangxi. But there exist problems of groundwater exploitation, groundwater pollution and natural disasters in these areas due to a special geological structure. Besides, the karst hydrological process is critical driving force for the sustainable development of ecological environment in karst areas; therefore, understanding mechanism of hydrological process is the key to the problem of ecological environment. Hydrochemical characteristics are closely related to hydrodynamics in a karst groundwater system, and hydrochemical tracers have been successfully used to indicate recharging sources, flow paths and water flow velocities.
Taking Maocun underground river basin in peak-cluster depression in Guilin, Guangxi as an example, we interpret water flow characteristics in the study area based on the hydrodynamic processes indicated by hydrochemical environmental tracers. Temporal and spatial variations of isotopes and their influence factors, especially those of stable environmental isotopes as natural tracers of water cycle, are suitable for indicating water flow characteristics and hydrodynamic processes in karst areas. Variation ranges of δD and δ18O of karst water samples fall in the ranges of local precipitation, indicating that precipitation is the main recharge source in the study area. Dissolved inorganic carbon (DIC) in karst water is approximately equal to
${\rm{HCO}}_3^{-}$ ${\rm{HCO}}_3^{-}$ In southwestern karst areas, karst is well developed with the characteristics of special dual structure. Surface water and shallow groundwater is well connected, the retention time of shallow groundwater is short, and hydrological processes are sensitive to precipitation or artificial influences. 222Rn with the half-time of 3.82 d is the decay product of radioactive uranium and radium, which can be used to determine the characteristics of karst hydrological processes on a short-time scale. Different types of water bodies are of significant differences in the values of 222Rn, which can indicate the seasonal variation characteristics of groundwater levels, fractured karst networks, karst water cycles and water flow patterns.
Electrical conductivity (EC) in the karst groundwater system is determined by interaction time of water and carbonate, which could be used to interpret ratios of recharing sources, groundwater flow patterns and structure characteristics of aquifer system. The complex spatial structures of karst aquifers interpreted by the responding characteristics of 222Rn and EC values to the precipitation show that karst water is recharged by different sources and water flow paths under different meteorological and hydrological conditions.
Precipitation is driving force of water flow in karst areas. Accumulated precipitation can drive fractured water of deep karst flow to the downstream with strong dilution. The larger the amount of precipitation is, the faster the velocity of karst water flow is. The dispersed fissure flow is the main pattern in the karst aquifer system under the situation of less precipitation in August. Because the flow time in the conduit is longer than the half-time of 222Rn (3.82 d), decay characteristics of 222Rn (3.82 d) cannot be used to calculate the flow velocity of karst water. Accumulated precipitation could drive fractured water of the deep karst and conduit water to flow to the downstream under the situation of heavy precipitation in June. The flow time of conduit water from Dayanqian to outlet is 0.82 d (<3.82 d). The influence of water-carbonate interaction on222Rn can be ignored, and the decay characteristics of 222Rn can be used to interpret flow patterns of conduit water in the rainy season. Based on the decay model of 222Rn in June, the effective water flow velocity in the underground conduit is 2,427.49 m·d−1, which is in the same order of magnitude as the results calculated by artificial tracers. Therefore, the decay characteristics of 222Rn can effectively reflect water flow patterns of conduits in the rainy season.
Water flow patterns in the underground river of southwest China are similar to those of surface water, and the underground river responds sensitively to precipitation. Due to the limitations of spatial characteristics indicated by artificial tracers, they cannot be used to interpret spatial structure characteristics of a karst aquifer system. However, hydraulic connection of the karst aquifer system can be interpreted by the interrelationships among SI, 222Rn, δ18O and δ13CDIC of water samples located in the transition zone from non-karst areas to karst areas. Karst water in Xiaolongbei, Laolongshui, Bianyan and Shanwan are well connected hydraulicly. The good linear relationships among Beidiping-Shegengyan-Outlet and Laolongshui-Dayanqian-Outlet by environmental tracers indicate that there are complex water flow paths recharging the outlet in the underground river basin. Environmental isotopes can divide karst water samples into several groups, and better interpret water flow paths and spatial structure characteristics of karst aquifer system. Therefore, hydrochemical environmental tracers can provide important information of a karst aquifer system, interpret multiple flow characteristics and compensate for drawbacks of hydrodynamic methods.
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Key words:
- environmental isotopes /
- Maocun underground river basin /
- water flow /
- spatial structure
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表 1 2021年6月和8月监测的水体δD、δ18O和δ13CDIC值
Table 1. Monitoring values of δD、δ18O and δ13CDIC in June and August of 2021
监测点 6月26日 8月28日 δD/‰ δ18O/‰ δ13CDIC/‰ δD/‰ δ18O/‰ δ13CDIC/‰ 小龙背 −34.48 −6.09 −9.50 −34.42 −5.88 −15.84 老龙水 −34.13 −5.99 −13.36 −34.21 −5.94 −13.91 扁岩 −33.08 −5.93 −14.33 −33.42 −5.87 −15.86 社更岩 −31.55 −5.72 −14.90 −33.64 −5.88 −14.14 山湾泉 −32.27 −5.80 −13.76 −33.13 −5.82 −14.00 背地坪 −30.73 −5.60 −15.79 −32.02 −5.66 −16.41 穿岩 −31.91 −5.66 −13.83 −33.09 −5.80 −13.87 大岩前 −31.82 −5.69 −13.67 −33.84 −5.83 −13.63 毛村出口 −31.60 −5.66 −13.89 −32.93 −5.75 −14.23 
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表 2 2021年6月和8月监测的水体222Rn和EC值
Table 2. Monitoring values of 222Rn and EC in June and August of 2021
监测点 6月26日 8月28日 222Rn/Bq·L−1 EC/µs·cm−1 222Rn/Bq·L−1 EC/µs·cm−1 小龙背 0.09 23.6 0.20 20.0 老龙水 5.87 284.7 2.15 324.3 扁岩 10.83 118.8 11.86 228.6 社更岩 4.34 262.0 19.13 285.7 山湾泉 18.58 230.3 5.62 293.0 背地坪 6.42 457.7 2.58 506.5 穿岩 17.10 332.4 15.70 360.9 大岩前 3.65 323.5 16.10 362.2 毛村出口 2.49 342.3 0.70 377.9
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[1] 袁道先. 中国岩溶学[M]. 北京: 地质出版社, 1994.
YUAN Daoxian. Karst Science in China [M]. Beijing: Geological Publishing House, 1994.
[2] 袁道先. 我国岩溶资源环境领域的创新问题[J]. 中国岩溶, 2015, 34(2):98-100. doi: 10.11932/karst20150201
YUAN Daoxian. Scientific innovation in karst resources and environment research field of China[J]. Carsologica Sinca, 2015, 34(2):98-100. doi: 10.11932/karst20150201
[3] 郭纯青, 方荣杰, 于映华. 中国南方岩溶区岩溶地下河系统复杂水流运动特征[J]. 桂林理工大学学报, 2010, 30(4):507-511. doi: 10.3969/j.issn.1674-9057.2010.04.007
GUO Chunqing, FANG Rongjie, YU Yinghua. Complex water movement in underground river system in south China karst area[J]. Journal of Guilin University of Technology, 2010, 30(4):507-511. doi: 10.3969/j.issn.1674-9057.2010.04.007
[4] 李建鸿, 蒲俊兵, 张陶, 王赛男. 相关和频谱分析法在岩溶系统中的应用研究综述[J]. 中国岩溶, 2020, 39(3):335-344.
LI Jianhong, PU Junbing, ZHANG Tao, WANG Sainan. Review on application of correlation and spectrum analyses in karst system research[J]. Carsologica Sinca, 2020, 39(3):335-344.
[5] 樊连杰, 邹胜章, 解庆林, 卢丽, 林永生, 朱丹尼, 王佳, 周长松, 李军. 乌蒙山区地下水赋存独特性与开发利用模式:以昭觉地区为例[J]. 地质学报, 2021, 95(11):3544-3555. doi: 10.3969/j.issn.0001-5717.2021.11.026
FAN Lianjie, ZOU Shengzhang, XIE Qinglin, LU Li, LIN Yongsheng, ZHU Danni, WANG Jia, ZHOU Changsong, LI Jun. Unique characteristics of groundwater occurrence and its development and utilization model in the Wumeng Mountain area : A case study of the Zhaojue area[J]. Acta Geologica Sinica, 2021, 95(11):3544-3555. doi: 10.3969/j.issn.0001-5717.2021.11.026
[6] 陶小虎, 赵坚, 陈孝兵, 甘磊, 邱莉婷. 岩溶含水层水流模型研究进展[J]. 水利水电科技进展, 2014, 34(2):76-84.
TAO Xiaohu, ZHAO Jian, CHEN Xiaobing, GAN Lei, QIU Liting. Research progress in numerical models for water flow in karst aquifer[J]. Advances in Sciences and Technology of Water Resources, 2014, 34(2):76-84.
[7] PAVLOVSKIY I, SELLE B. Integrating hydrogeochemical, hydrogeological, and environmental tracer data to understand groundwater flow for a karstified aquifer system[J]. Groundwater, 2015, 53(1):156-165.
[8] 韩行瑞. 岩溶水文地质学[M]. 北京: 科学出版社, 2015.
HAN Xingrui. Karst Hydrogeology[M]. Beijing: Science Press, 2015.
[9] 郭永丽, 章程, 吴庆, 全洗强. 岩溶裂隙含水层中石油类有机物的自然衰减机制[J]. 地球科学, 2021, 46(6):2258-2266.
GUO Yongli, ZHANG Cheng, WU Qing, QUAN Xiqiang. Natural attenuation mechanisms of petroleum hydrocarbons in a fractured karst aquifer[J]. Earth Science, 2021, 46(6):2258-2266.
[10] 郭清海, 王焰新. 水文地球化学信息对岩溶地下水流动系统特征的指示意义: 以山西神头泉域为例[J]. 地质科技情报, 2006, 25(3):85-88.
GUO Qinghai, WANG Yanxin. Hydrogeochemistry as an indicator for karst groundwater flow: A case study in the Shentou karst water system, Shanxi, China[J]. Geological Science and Technology Information, 2006, 25(3):85-88.
[11] LAUBER U, GOLDSCHEIDER N. Use of artificial and natural tracers to assess groundwater transit-time distribution and flow systems in a high-alpine karst system (Wetterstein Mountains, Germany)[J]. Hydrogeology Journal, 2014, 22(8):1807-1824. doi: 10.1007/s10040-014-1173-6
[12] 姜光辉, 于奭, 常勇. 利用水化学方法识别岩溶水文系统中的径流[J]. 吉林大学学报:地球科学版, 2011, 41(5):1535-1541.
JIANG Guanghui, YU Shi, CHANG Yong. Identification of runoff in karst drainage system using hydrochemical method[J]. Journal of Jilin University (Earth Science Edition), 2011, 41(5):1535-1541.
[13] VESPER D J, WHITE W B. Storm pulse chemographs of saturation index and carbon dioxide pressure: implications for shifting recharge sources during storm events in the karst aquifer at Fort Campbell, Kentucky/Tennessee, USA[J]. Hydrogeology Journal, 2004, 12(1):135-143.
[14] MANCE D, HUNJAK T, LENAC D, RUBINIĆ J, ROLLER-LUTZ Z. Stable isotope analysis of the karst hydrological systems in the Bay of Kvarner (Croatia)[J]. Applied Radiation and Isotopes, 2014, 90(4):23-34.
[15] RUSJAN S, SAPAČ K, PETRIČ M, LOJEN S, BEZAK N. Identifying the hydrological behavior of a complex karst system using stable isotopes[J]. Journal of Hydrology, 2019, 577(10):123956.
[16] 蒲俊兵. 重庆岩溶地下水氢氧稳定同位素地球化学特征[J]. 地球学报, 2013, 34(6):713-722. doi: 10.3975/cagsb.2013.06.08
PU Junbing. Hydrogen and oxygen isotope geochemistry of karst groundwater in Chongqing[J]. Acta Geoscientica Sinica, 2013, 34(6):713-722. doi: 10.3975/cagsb.2013.06.08
[17] VRZEL J, SOLOMON D K, BLAZEKA Ž, OGRINC N. The study of the interactions between groundwater and Sava River water in the Ljubljansko polje aquifer system (Slovenia)[J]. Journal of Hydrology, 2018, 556(1):384-396.
[18] GIL-MÁRQUEZ J M, SÜLTENFUƁ J, ANDREO B, MUDARRA M. Groundwater dating tools (3H, 3He, 4He, CFC-12, SF6) coupled with hydrochemistry to evaluate the hydrogeological functioning of complex evaporite-karst settings[J]. Journal of Hydrology, 2020, 580(1):124263.
[19] FALCONE R A, FALGIANI A, PARISSE B, PETITTA M, SPIZZICO M, TALLINI M. Chemical and isotopic (δ18O‰, δ2H‰, δ13C‰, 222Rn) multi-tracing for groundwater conceptual model of carbonate aquifer (Gran Sasso INFN underground laboratory-central Italy[J]. Journal of Hydrology, 2008, 357(3):368-388.
[20] GUO Y L, WU Q, JIANG G H, HAN Z W, TANG Q J, QUAN X Q. Dynamic variation characteristics of water chemistries and isotopes in a typical karst aquiferous system and their implications for the local karst water cycle, Southwest China[J]. Carbonate and Evaporites, 2019, 34(3):987-1001. doi: 10.1007/s13146-018-0457-7
[21] 蒋然, 朱小平, 梁志宏, 雷列辉, 刘艺斯. 桂林毛村地下河水质评价[J]. 水资源保护, 2016, 32(5):85-90. doi: 10.3880/j.issn.1004-6933.2016.05.017
JIANG Ran, ZHU Xiaoping, LIANG Zhihong, LEI Liehui, LIU Yisi. Water quality evaluation in subterranean river at Maocun village in Guilin[J]. Water Resources Protection, 2016, 32(5):85-90. doi: 10.3880/j.issn.1004-6933.2016.05.017
[22] 莫春梦. 桂林市毛村流域碳酸盐岩混合溶蚀实验研究[D]. 北京: 中国地质大学(北京), 2019.
MO Chunmeng. Experimental study on mixed dissolution of carbonate rocks in Maocun watershed of Guilin [D]. Beijing: China University of Geosciences (Beijing), 2019.
[23] 黄芬. 漓江流域氮素对岩溶碳循环过程的影响机制[D]. 北京: 中国地质科学院, 2020.
HUANG Fen. Impact of nitrogen on karst carbon cycle in the Lijiang river basin [D]. Beijing: Chinese Academy of Geological Science, 2020.
[24] XIE Y, YANG L, ZHU T B, YANG H, ZHANG J B, YANG J L, CAO J H, BAI B, JIANG Z C, LIANG Y M, LAN F N, MENG L, MÜLLER C. Rapid recovery of nitrogen retention capacity in a subtropical acidic soil following afforestation[J]. Soil Biology and Biochemistry, 2018, 120(5):171-180.
[25] YANG H, ZHANG P, ZHU T B, LI Q, CAO J H. The characteristics of soil C, N, and P stoichiometric ratios as affected by geological background in a karst graben area, Southwest China[J]. Forests, 2019, 10(7):601. doi: 10.3390/f10070601
[26] 尹伟璐. 桂林市毛村流域岩溶含水介质及碳汇效应研究[D]. 北京: 中国地质大学(北京), 2016.
YIN Weilu. Study on karst aquifer medium and carbon sink effect in Maocun river basin of Guilin [D]. Beijing: China University of Geosciences (Beijing), 2016.
[27] 朱昊. 岩溶含水介质刻画: 以桂林毛村流域为例[D]. 北京: 中国地质大学(北京), 2017.
ZHU Hao. Description for karst aquifer medium: a case study in Maocun basin of Guilin [D].Beijing:China University of Geosciences (Beijing), 2017.
[28] 李彬, 林玉石, 徐胜友. 桂、湘某些岩溶洞穴氡及其子体分布特征的初步研究[J]. 中国岩溶, 1995, 14(4):345-351.
LI Bin, LIN Yushi, XU Shengyou. A preliminary study of radon in the caves of Guangxi and Hunan, China[J]. Carsologica Sinica, 1995, 14(4):345-351.
[29] 罗国煜, 刘广才. 放射性氡污染及其环境岩土工程问题[J]. 工程勘察, 1988, 5:1-5.
LUO Guoyu, LIU Guangcai. Polluton of radioactive radon and its application in solving environmental engineering[J]. Engineering Inverstigation, 1988, 5:1-5.
[30] 郭芳, 韦丽琼, 姜光辉. 广西典型岩溶水系统环境中222Rn的分布及指示意义[J]. 中国环境科学, 2021, 41(9):4294-4299. doi: 10.3969/j.issn.1000-6923.2021.09.036
GUO Fang, WEI Liqiong, JIANG Guanghui. Characteristic of radon in typical karst water systems and its indicating significance in Guangxi, China[J]. China Environmental Science, 2021, 41(9):4294-4299. doi: 10.3969/j.issn.1000-6923.2021.09.036
[31] BASKARAN M. Randon: A tracer for geological, geophysical and geochemical studies [M]. Springer International Publishing Switzerland, 2016.
[32] 张春来, 黄芬, 蒲俊兵, 曹建华. 中国岩溶碳汇通量估算与人工干预增汇途径[J]. 中国地质调查, 2021, 8(4):40-52. doi: 10.19388/j.zgdzdc.2021.04.05
ZHANG Chunlai, HUANG Fen, PU Junbing, CAO Jianhua. Estimation of karst carbon sink fluxes and manual intervention to increase carbon sinks in China[J]. Geological Survey of China, 2021, 8(4):40-52. doi: 10.19388/j.zgdzdc.2021.04.05
[33] 吴夏, 朱晓燕, 张美良, 白晓, 张碧云. 大气降水中稳定同位素组成的高分辨率记录: 以桂林地区为例[J]. 长江流域资源与环境, 2013, 22(2):182-188.
WU Xia, ZHU Xiaoyan, ZHANG Meiliang, BAI Xiao, ZHANG Biyun. High-resolution stable isotope record of atmospheric precipitation in Guilin[J]. Resources and Environment in the Yangtze Basin, 2013, 22(2):182-188.
[34] TALLINI M, PARISSE B, PETITTA M, SPIZZICO M. Long-term spatio-temporal hydrochemical and 222Rn tracing to investigate groundwater flow and water-rock interaction in the Gran Sasso (central Italy) carbonate aquifer[J]. Hydrogeology Journal, 2013, 21(7):1447-1467. doi: 10.1007/s10040-013-1023-y
[35] MASSEI N, MAHLER B J, BAKALOWICZ M, FOURNIER M, DUPONT J P. Quantitative interpretation of specific conductance frequency distributions in karst[J]. Groundwater, 2007, 45(3):288-293. doi: 10.1111/j.1745-6584.2006.00291.x
[36] 郭芳, 姜光辉, 刘绍华, 汤庆佳. 利用电导率频率分布辨别岩溶含水系统的水源组分[J]. 水科学进展, 2018, 29(2):245-251.
GUO Fang, JIANG Guanghui, LIU Shaohua, TANG Qingjia. Identifying source water compositions of karst water systems by quantifying the conductance frequency distribution of springs[J]. Advances in Water Science, 2018, 29(2):245-251.
[37] TADOLINI T, SPIZZICO M. Relation between "terra rossa" from the Apulia aquifer of Italy and the radon content of groundwater: experimental results and their applicability to radon occurrence in the aquifer[J]. Hydrogeology Journal, 1998, 6(3):450-454. doi: 10.1007/s100400050167
[38] 汪丙国. 地下水补给评价方法研究: 以华北平原为例[D]. 武汉: 中国地质大学(武汉), 2008.
WANG Bingguo. Research on estimating methods of groundwater recharge: A case study in North China plain [D]. Wuhan: China University of Geosciences (Wuhan), 2008.
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