The groundwater level distribution and characteristics of responses to rainfall were examined in the Haean basin of Yangu that has a single stream exit to the east. The groundwater levels showed a circular or elliptical distribution converging the center of the basin with different hydraulic gradients in the north and south regions. The waterlevel elevations exhibited a perfect correlation with topographic elevation (
r2=0.99) while the depth to water showed a rather weak correlation (
r2=0.49). The water table fluctuation (WTF) method yielded recharge ratios of 6.1~12.65% (
Sy=0.02) and 15.2~28.5% (
Sy=0.05). The waterlevels of HG3 well, which is much proximal to a stream, were weakly auto-correlated but they were highly sensitive to direct infiltration from the rainfall event. The shorter regulation times of the HG3 represented a quicker dissipation of the input stress (rainfall).
Keywords: Basin area;Waterlevel;Groundwater recharge;Autocorrelation;Spectral density function;