Haha, i have been to chapora fort but did not make it to the Aguada one have a great pic of the peninsula opposite it, it's funny that you say these are porous because i was looking at the statue of liberty base and saw this, to me this looks like a run off like they have in big reservoirsI found another Star Fort while traveling in India. This one is in ruins, called Chapora Fort. It is in an area called Vagator, part of former Portugese colony, also once ruled by Indian king dynasty and Muslim rule, called Goa.
This is the third star fort I have found in Goa India.
Chapora Fort (ruined)
Aguada Fort (definitely maaaany underground tunnels visible, and many arches within the star fort walls, and a deep cistern/well underneath the fort. I saw throigh covered gates at least 40 feet underground passageways, with natural light "skylights" on the level ground within the walls of the fort)
Another is called Reis Magos Fort (I havent visited it in person yet) - Reis Magos refers to the King Magicians of the east refered to in Christian Scripture (We Three Kings of Orient are...)
The walls of all these star forts were built using LATERITE a unique substance which is considered a stone AND a soil. They dig it out of the hillsides and out of the ground. It is porous and holds water, so it slowly releases moisture to trees and vegetation, even if it only rains ocassionally in the dry season.
Aerial view I found online, and a screenshot from G00gle Earth