The purpose of this study was to trace the groundwater flow system in the Nagaoka area
using subsurface temperature distribution, stable isotopes and water quality. Temperature-
depth profiles were measured four times in observation wells during the period 2000–2002.
Water was sampled from both observation and pumping wells during the same period. A
combination of tracers was used to conceptualize the groundwater flow system. The flow
system appears to be divided into shallow, intermediate and deep systems. It is clear that …

In this study, we use borehole temperature data and stable isotopes to delineate the flow
system and estimate the effect of urbanization in the Nagaoka area of Japan. Temperature
profiles were measured four times in observation wells during the period 2000–2001 and
compared with those measured in the same wells during the period 1977–1983 (Taniguchi
1986). Water was sampled in both observation and pumping wells during the same period.
The temporal and spatial variability in temperature indicate clearly the effect of urban …