kuttam pokuna or the twin ponds are another hydrologic engineering marvels of the ancient sri lanka. these two ponds belong to the abayagiri aramic complex and probably been used by the monks for bathing. the origins of these ponds are not known but it is thought to have been built during the reign of king aggabodhi i (575-608).
the smaller pond (the northern) one has been constructed first and the larger one at a later stage. they are connected through a pipeline at the bottom. the northern pond is 91 feet (28 meters) long and the other 132 feet (40 meters) .
water to these ponds have been supplied through underground pipelines and the water is sent through several filtering chambers before it falls on the northern pond through a mouth of a dragon. the water from both ponds is drained from a small outlet in the smaller northern pond.
though the underground pipelines are no more, you can see 4 levels of filtering of the water before it enters the ponds.