ZHU Biao¹, CHEN Xi^1,2, ZHANG Zhicai¹, PENG Tao³, ZHANG Lechen⁴, CHEN Bo³, ZHAO Meigang³

（1. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China;
2. Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China;
3. Puding Karst Ecosystem Research Station, Chinese Ecosystem Research Network （CERN）, CAS, Guizhou Puding 562100, China;
4. Huadian Electric Power Research Institute Co. LTD, Hangzhou 310030,China）

Abstract: The hydrodynamic and the material circulation processes in southwestern karst basins are very complex because of the special hydrogeological conditions. It is difficult to analyze the hydrodynamic process in these regions by using a single piece of hydrological information. Groundwater conductivity is affected by karst hydrogeological conditions, which comprehensively reflects regional hydrodynamic conditions and lithological characteristics. In this paper, the Houzhai River Basin in Puding County, Guizhou Province, is selected as the research area. Through field investigation and in-situ measurement of groundwater conductivity, combined with spatial distribution laws of karst topography, lithology, falling water caves and karst springs, the spatial distribution of groundwater conductivity and its influence by water-rock characteristics in the karst basin in dry season are analyzed. The results show that the groundwater conductivity in the hilly area, a strong runoff area with karst fissure/pipeline network development, is low because, mainly, the water-rock contact time is short. The conductivity of groundwater shows an increasing trend with the decrease of elevation, which indicates that the velocity of groundwater flow slows down and the water-rock contact time becomes longer. Groundwater conductivity is significantly affected by lithological characteristics. The water-rock interaction is strong in limestone areas, and it is easy to form groundwater with a high average conductivity of 650 μS/cm. The water-rock interaction is weakened in dolomite areas and the average groundwater conductivity is reduced to 523μS/cm.

Key words: Karst basin；specific electrical conductivity；hydrodynamic condition；rock；dry season

EARTH AND ENVIRONMENT Vol.47, No.4, Tot No.330, 2019, Page 459-463