Tissa Wewa, which is the third oldest tank in Anuradhapura archeological area is an artificial reservoir built by the king Devanampiya Tissa in 3rd century BC. It can be considered as a symbol of ancient irrigation systems in Sri Lanka. It is located in the south west of the city. The tank was built with the aim of increasing the water supply to the capital city of Anuradhapura. Also the tank supplied water to the ponds in the Royal pleasure garden in Ranmasu Uyana, which is situated next to Isurumuniya temple. The water was irrigated under a regional network of irrigation canals. Even today, the tank continuously feed water to Anuradhapura city.
The embankment of Tissa Wewa which is solidly made and remaining undamaged until today is approximately 11000 feet in distance and 25 feet in depth. The tank has the area of nearly 550 acres. Tissa wewa receives water from Kalawewa through the ancient canal called Jaya ganga, another great creation of ancient architectures. The excess water of the tank is released to the famous Malwathu Oya.
When constructing artificial tanks, the rulers considered geographical features thoroughly to make sure the construction would be fruitful and never fail. Tissa wewa is such example where the ancient kings paid their utmost attention to develop tanks and maintain water resource as it closely associated with Sri Lankan life style. They never let anybody to waste a single drop of water.