Interaction between groundwater quality and hydraulic head in an area around an underground LPG storage cavern, Korea

Abstract.

The interactive influence between groundwater flow and salinization that occurs in an underground LPG cavern site in Korea was investigated using chemical analysis data and cross-correlation analysis between hydraulic head and operating pressure data. The concentration of the major cations and anions showed a large difference between rainy and dry seasons due to the seasonal intrusion of highly saline water into the cavern area. However, the Cl/Br ratio and δ¹⁸O–Cl relationship showed that two types of saline water (seawater and halite-dissolved solution) influenced the groundwater salinization of the study area. The cross-correlation results revealed that a positive relationship between hydraulic head and cavern operating pressure was far more conspicuous in the propane cavern area (89–91% of correlation coefficients), and tidal change influenced the head variation in the butane cavern area. That is, continuous intrusion of seawater near the South Sea could bring about a high concentration of major cations and anions in the butane seepage waters and groundwaters near the coastal area, and seasonal variation in the operating pressure at the propane cavern played an important driving force in fast infiltration of halite-dissolved solution from surface halite stock and a subsequent increase in Na and Cl concentration during the dry season.