Sri Lanka has two large monsoon seasons, which last for about three months. The rest of the year is dry and hot, with the exception of a few thunderstorms that cause a bit of heat at night. This climate can have a devastating impact on those who live off agriculture due to lack of regular water. In an effort to alleviate this problem, many ancient kings built water-regulating tanks.
The Parakrama Samudra (or the Sea of Parakrama King or Parakrama King’s Sea) was a shallow reservoir, built by King Parakramabahu the Great (1153-1186) and what you see today as Parakrama Samudra is only part of his original design. The Parakrama Samudra originally consisted of five large reservoirs separated by small dams to reduce the pressure on the main dam. Many small tanks have been built around the main tank to feed these primary tanks and to supply the excess water.
The main reservoirs consisting of Parakrama Samudraya are Thoppa wewa, Eramudu wewa (thorn wewa), Dumbuthula wewa, Kalahagala wewa and Bhu wewa. During the reconstruction of the Parakrama Samudra in the latter part of the 19th century, the water flowing to the Topa Lake had begun to flow to the ground. To control this, engineers built a makeshift dam to block the flow of water to the lake. The temporary dam became a permanent road and the road was isolated from the Parakrama Samudra of Kalagala wewa and Bhu wawa.
The new technology has neglected the old technology that built the tank to further reduce tank capacity. Today the Parakrama Samudra Dam is 8 miles (14 km) long and 40 feet (12.2 m) high. The average water depth of 5350 acres is about 25 feet. The reservoir provides water to over 18,000 acres of paddy fields.
The term “Wave Bendi Rata” (Reservoir ) is used to describe the city of Polonnaruwa because there is a large number of tanks. One of them is the Parakrama Samudra.