Kuttam Pokuna or Twin Ponds are one of the engineering wonders of ancient Sri Lankan architecture. These ponds are believed to be use by monks for bathing and build during the "King Aggabodhi I" (575-608) period. The smaller pond (northern pond) was build first which is 28 meters long and later the longer pond (40 meters) was build. Both are connected with pipe line which runs from underneath.
Water was send though a underground pipe line to the northern pond and water gone through a filtering system before it comes to the north pond through a Dragon mouth.
Source - amazinglanka
I would like share some of the photos I have captured during my visit,
The larger pond
The smaller pond
The water inlet (Dragon mouth)
The water filters
Unfortunately I could not able to capture the water filtering system. here I am attaching few photos from internet for your reference.
Source - amazinglanka