If the collecting rim (opening to the outside) is damaged in any way, the amount of precipitation being measured will be changed because less water can enter the gauge than it was calibrated for.
(it; was calibrated; T:for) (the collecting rim; is damaged; ) (precipitation; being measured; ) (the amount of precipitation; will be changed; because less water can enter the gauge than it was calibrated for) (less water; can enter; the gauge)
it the collecting rim precipitation the amount of precipitation less water
was calibrated is damaged being measured will be changed can enter
T:for
because less water can enter the gauge than it was calibrated for
the gauge