Assertion: aquifer's part | /r/CapableOf | become filled
Facets:
value: partially
type: DEGREE
value: at that location
type: LOCATION
Source sentences:
text: If water levels decline below the top of a confined aquifer, the aquifer becomes unconfined (that is, the upper part of the aquifer becomes partially air filled) at that location and the fluid pressure becomes zero transferring all the stress to the aquifer matrix.