Hydrogeological and hydrogeochemical studies for salt water intrusion on the south coast of Laizhou Bay, China

Sea water intrusion has occurred on the east and southeast coasts of Laizhou Bay, China, since the 1970s (Wu et al, 1993). In 1981, on the adjacent south coast, the intrusion of salt water originating from brine was observed. In this area, the salt water intrusion was caused by the excessive pumping of fresh water in aquifers, Moreover, the simultaneous pumping of fresh water and salt water/brine formed a complicated ground water flow field. The data obtained from observation webs were used to analyze the origin of the salt water and brine, and the genesis of the bicarbonate/sodium water zone. All data suggest that the brine originated from ancient sea water, and that the bicarbonate/sodium water was formed by cation exchange, The variations of chemical compositions along representative flowpaths and the relationships between such variations and salt water intrusion were also discussed.