I'm writing a story that takes place at three different dragon reserves: the one Charlie works at in Romania, one somewhere in northern Italy, and the MacFusty wizard clan's Hibredian Black reserve in the Hebrides.

How large do you think a dragon reservoir would have to be?

How would they conceal it from Muggles?

How would you imagine it to look from the air? Would you have to look for monuments to realize it's there or would Wizards be able to see it?

Thanks in advance!