rainfall were distinctly higher than the groundwater and well water.
It was suggested that the groundwater was not recharged by
the local precipitation. The Cl concentration (Fig. 8a) in this profile
also supports this conclusion. The curve shows that the Cl is
concentrated in the depth of 20e30 cm. If the precipitation can
always reach the groundwater, the Cl peak cannot form on the
profile, because the Cl can easily move with the rainfall. The Cl
profile in Fig. 8b shows several peaks more clearly. The first peak is
near the surface, which should be formed by the evaporation of
rainfall. Two connected peaks are distributed at the depth of
100e110 cm with a mean Cl concentration of 651 mg/L. And the
Cl concentration of the largest peak is 2392 mg/L at 250 cm. The
mean Cl concentration at the depth of 100e350 cm is 343 mg/L
while the upper 0e100 cm has a mean concentration of 115 mg/L.