Underground rivers serve as a key groundwater storage mechanism in the karst regions of Southwest China. A comprehensive understanding of their structural characteristics and flow pathways is crucial for groundwater resource assessment, protection, and engineering applications. Taking the Pingjiang underground river as a case study, the architecture of karst conduits and flow dynamics were investigated through tracer tests, hydrogeochemical monitoring, and integration of hydrogeological data. The results revealed that the groundwater in the Pingjiang underground river is of the HCO3-Ca type, with hydrochemical composition primarily shaped by leaching processes. Stable isotope ratios (δD and δ18O) were found to exhibit a progressive enrichment trend along the flow direction, indicating that water-rock interaction was enhanced and the system confinement in the downstream segment was relatively greater compared to the middle and upper reaches. The Pingjiang system was characterized as a multi-source, single-sink underground river, with dendritically distributed karst conduits comprising one main conduit and four tributaries. The breakthrough curve from the tracer test in the main conduit displayed a distinct “plateau” feature, suggesting the coexistence of well-developed conduits and fractures, as well as the presence of multiple transient storage zones along the flow path. These findings provide valuable insights for the investigation, development, and sustainable utilization of groundwater resources in complex karst aquifer systems.
QIN Jia-xiao, ZHENG Huan-jun, BEI Wei-chang, WANG Quan-rong, ZHANG Qin-jun, HUANG Chun-yang, HUANG Zhi-wei, CHEN Yu-dao.
Analysis of Karst Water System Characteristics Based on Tracer Tests and Hydrochemistry: Pingjiang Underground River[J].
Science Technology and Engineering, 2026, 26(10): 4055-4065 DOI:10.12404/j.issn.1671-1815.2504295
YangPingheng, HuaMaosong, LuoWeiqun, et al. Research progress of nitrate tracing in karst groundwater based on CiteSpace[J]. Carsologica Sinica, 2024, 43(3): 563-574.
ShanHaiping, DengJun. Basic features and countermeasures for harmonious use of karst water in southwest China[J]. Carsologica Sinica, 2006(4): 324-329.
[5]
SharmaK P, JoshiN, OjhaC. Stochastic numerical method for analysis of solute transport in fractured porous media[J]. Journal of Hydro-environment Research, 2013, 7 (1): 61-71.
GuoYongli, WuPeiyan, HuangFen, et al. Water flow characteristics of Maocun underground river basin based on environmental isotopes[J]. Carsologica Sinica, 2022, 41(4): 577-587.
[8]
WangY, ZhaoR, DingL, et al. Karst trough control of solute transport processes at two karst groundwater flow systems, western Hubei, central China[J]. Journal of Earth Science, 2025, 36(4): 1731-1741.
[9]
BenischkeR. Review: advances in the methodology and application of tracing in karst aquifers[J]. Hydrogeology Journal, 2021, 29: 67-88.
NingJiaqi, FengZijun, GaoQi. Tracer migration characteristics of complex fractured rock mass under fracture-porosity dual media model[J]. Science Technology and Engineering, 2025, 25(7): 2904-2913.
ZhaoXiaoer, WangZhengyi, WuGuizhi, et al. Research on the scale effects of solute transport in a bended karst conduit[J]. Hydrogeology & Engineering Geology, 2023, 50(2): 44-53.
WuPing, GeQin, ZhangWeimin, et al. Tracing hydraulic connection of a karst aquifer system based on hydrochemistry and isotopes: a case study of the Auxiliary Dam of Sifangjing in Yichun City[J]. Science Technology and Engineering, 2021, 21(28): 12058-12065.
[16]
DuranL, GillL W. Modeling spring flow of an Irish karst catchment using Modflow-USG with CLN[J]. Journal of Hydrology, 2021. DOI: 10.1016/j.jhydrol.2021.125971.
FanShijie, YangYanna, XuMo, et al. Measurement of cavity connectivity and pipeline’s hydraulic parameters based on tracer test[J]. Journal of Changjiang River Scientific Research Institute, 2022, 39(6): 64-68.
WangGuanghao, ZhangYing, XuLiangliang, et al. Relationship between surface water and groundwater transformation in Qu River Basin[J]. Science Technology and Engineering, 2021, 21(15): 6165-6174.
LiWei, GengHan, SuChunli, et al. Hydrochemical evolution processes and mechanism of groundwater iron and sulfate pollution in Daye Mining area[J]. Safety and Environmental Engineering, 2023, 30(2): 223-232.
[23]
ZhangF, WuB, GaoF, et al. Hydrochemical characteristics of groundwater and evaluation of water quality in arid area of northwest China: a case study in the plain area of Kuitun River Basin[J]. Arabian Journal of Geosciences, 2021, 14(20). DOI: 10.1007/S12517-021-08464-7.
PanDeng, WangShuai, GuoHong, et al. Hydrogeochemical characteristics and recharge source identification of phreatic water in the lower reaches of the Yellow River(Henan section)[J]. Safety and Environmental Engineering, 2024, 31(4): 170-180.
[26]
PandeyA, PadhyaV, ChakraS, et al. Groundwater recharge in Central India and its spatio-temporal variation: insights and implications from oxygen and hydrogen isotope[J]. Journal of Hydrology, 2023, 617.DOI: 10.1016/J.JHYDROL.2022.129040.
MaBaoqiang, WangXiao, TangChao, et al. Main applications of isotope technology in groundwater study[J]. Journal of Environmental Engineering Technology, 2021, 11(5): 919-926.
[29]
RusjanS, SapaK, PetriM, et al. Identifying the hydrological behavior of a complex karst system using stable isotopes[J]. Journal of Hydrology, 2019, 577(10). DOI: 10.1016/j.jhydrol.2019.123956.
[30]
FatemehB, HosseinG K, RahimB, et al. Geochemical and multi-isotopes (δ18O, δ2H, δ13C, 3H and δ37Cl) evidences to karst development and flow directions in transboundary aquifer, Northeast of Iran[J]. Applied Geochemistry, 2021. DOI: 10.1016/J.APGEOCHEM.2021.105071.
LuXiaohui, WangMengyao, GongXulong, et al. Hydrogen and oxygen isotope based transformation studies of surface water and groundwater in plains lakes and swamps[J]. Journal of Hydraulic Engineering, 2024, 55(4): 416-427.
XieGuowen, YangPingheng, LuBingqing, et al. Application of high-resolution tracer technique in identifying the source of water gushing and the structure of aquifer medium in karst tunnel[J]. Carsologica Sinica, 2018, 37(6): 892-899.
[35]
RavbarN, PetriM, BlatnikM, et al. A multi-methodological approach to create improved indicators for the adequate karst water source protection[J]. Ecological Indicators, 2021, 126(1). DOI: 10.1016/j.ecolind.2021.107693.
ZhangLiang, LiJun, PanXiaodong, et al. Tracer test and analysis of groundwater system in a karst area of southwest China[J]. Carsologica Sinica, 2020, 39(1): 42-47.
YuanJing, ZhangDebing. Tracer-test-based technology of quantifying water flow connectivity between hunan and Guangxi Provinces[J]. Journal of Changjiang River Scientific Research Institute, 2023, 40(3): 25-29, 59.
LiaoJia, ZhuZhenhua, PengYi, et al. Analysis on D/18O and hydrochemical characteristics of karst groundwater in northwestern Hunan Province[J]. Carsologica Sinica, 2023, 42(3): 425-435, 481.
WangJingyi, LiuPu, ChenWeixiao, et al. Characterization and comprehensive evaluation of water quality of underground rivers in typical karst areas in Qianxinan Prefecture[J]. Science Technology and Engineering, 2024, 24(29): 12797-12808.
LiTengfag, QinXiaoqun, HuangQibo, et al. Groundwater tracer test and curve characteristics in karst area[J]. China Mining Magazine, 2019, 28(S2): 497-498, 501.
GengXinxin, ZhangFenger, ChenZongyu, et al. Characterization of karst conduit structure based on multisource artificial tracer test: a case study of the Cangpuwa underground river in Guizhou Province[J]. Bulletin of Geological Science and Technology, 2022, 41(5): 324-332.