Abstract
Land subsidence and saltwater intrusion into groundwater due to pumping up of the same are examples of the serious problems in this region. It is important to study on the characteristics of groundwater environment for conservation of geoenvironment. Recently, the tracer methods using such dissolved elements as cations/anions and gases, natural radioactive or stable isotopes have been used widely for study on groundwater circulatioa This paper describes the applicability of these tracer methods in Saga Plain. The results show that the groundwater in Saga Plain has been supplied from the surrounding mountainous districts. This study also shows that the age of groundwater at the foot of mountains is several decades, and that of the plain near Ariake Sea is about 103 years long.
