Abstract: This paper studied the anomalous variation of Baicheng's ZK6 well (deep) and ZK6-1 well (sha llow) water level caused by a strong rainstorm occurred in Baicheng city, Jilin Province on August 8, 1998. According to the fact we have recorded, we get the following result, i.e. this rainfall is a successful rainfall loading experiment, in a sense also an experiment of a large area water injection of shallow well. From this we can see that the applied mechanism to the water level of deep and shallow well caused by a rainfall is absolutely different. For the shallow well, it is a filter process, for the deep well, it is a rainfall loading process. This result will be of significance in eliminating the disturbance of rainfall on the observation of underg round water level.

Key words: Strong rainstorm, Water level anomaly, Rainfall loading