抄録
When unconfined ground water is pumped through a well, discontinuous water level arise at the well-wall.
It has been cleard by theory and tests the phenomenon is caused by the resistance of casing and vertical flow near the well-wall in the aquifer. The results are expressed as follows
1) When the opening area ratio of the casing is smaller than 10%, the discontinuous water level is mainly caused by the resistance of casing.
2) When the opening area ratio of the casing became larger and the ratio of pumping water level to static water level is smaller then 0,6, it is mainly caused by vertical flow near the well-wall in the aquifer.
Using this method, the properties of aquifer can be estimated more accurately through field test.
