The water in the gravel pit may come wholly or mainly from underground—which is normally where gravel pit water comes from.
That might make a neat regime, but it takes no account of the actual location of the gravel pit in a county.
They might fall, for instance, into a disused gravel pit, or branches of elm trees might fall upon them.
That is the case of a gravel pit.
The site is a worked out gravel pit.
Unlike a gravel pit, a well is not easily seen, and not easily quantifiable.
A large gravel pit or series of gravel pits may be in the ownership of an organisation specially interested in gravel.
The gravel pit is one of the most likely examples.