The famous Sorabora Wewa, the massive irrigation reservoir of ancient Bintanne lies about 1 km from the current Mahiyangana town and a must see destination for visitors of Mahiyangana Rajmaha Viharaya.
Sorabora Wewa which was called the Sea of Binthanne in the ancient past, is unique to all other ancient reservoirs a this is considered the only existing reservoir which does not make use of a Bisokotuwa, the heart of all other large reservoirs of the country. This ground breaking invention was the single factor which enabled the ancients to build massive reservoirs since 4th century BC.
Generally all the reservoirs have the sluice gates which regulate the water flow out of the reservoir on the massive embankments. It was the Bisokotuwa which regulated the water pressure at the sluice gates inside the tank and protected the embankment from erosion.
The builders of the Sorabora Wewa didn’t place the sluice gates at the embankment but used a strategically located natural rock away from the embankment and cut a deep canal which acted as the sluice for the tank. Since the rock was not subject to erosion by the pressure of water, the ancient builders had decided to do away with the tried and tested Bisokotuwa for this creation.
The Sorabora Tank is built damming the Diyawanna Oya with a 1590 feet (485 meter) embankment. The tank covers 1100 acres ( 4.5 sq km) and holds 11800 acre feet ( 14.6 Mn sq meters) of water at full capacity. The slice gates are expertly cut in to the natural rock and is about 5 feet wide.
The tank is believed to be built during the 2nd century BC when the warrior prince Gemunu was warring with the Tamil invader Elara by a relatively unknown general called Bulatha. When army of the prince Gemunu with his 10 generals (giants) was marching towards Anuradhapura, the army is said to have camped at the village called “Kadali Pathra” (today known as Keselpatha) near Mahiyangana, It was at this time a strongman called Bulatha (Balathirala) from the village of Kiripattiya in Ududumbara joined the army of the Gemunu.
The task which was assigned for Bulatha was to collect Treacle from Meemure, milk from Kiripattiya, betel leaves from Kevulgama, arecanut from Puwakpitiya ( today known as popepitiya)daily and deliver these to the kings castle. With all these villages separated by mountains his route was treacherous including the Kosgolla mountain pass which which connected the Ududumbara and Minipe area and also used by thousands of pilgrims visiting Mahiyangana Rajamaha Viharaya.
While making this daily trip, Bulatha noticed the a stream of water passing between two hills and released that if be could dam this stream, this could be an ideal location for a water reservoir which could provide water for thousands of paddy fields. So everyday after his daily trip to the palace with the supplies, he started building the embankment across two hills by himself.
Tradition says that Bulatha was so strong that this mamoty was 10 times bigger than the average mamoty and the basket to remove earth was equally large. His wife living at Kiripattiya too was a woman with a strength of 20 women. She used to travel daily to Mahiyanganaya over the Kosgolla mountain pass bringing Bulatha his meals while he was working on the dam.
Traveling over the treacherous Kosgolla twice a day and seeing thousands of young and old pilgrims travelling the same path, she decided to build a flight of steps over this path to help the pilgrims of Mahiyangana Rajamaha Viharaya. While carrying food to Bulatha, she started adding few stone steps everyday to this path.
When Bulatha completed the reservoir with a 40 feet tall and 11 feet wide embankment which stretched to about 500 meters complete with a unique slice gate away from the embankment cut through a solid natural rock, the wife too has completed her herculean task of adding 2000 stone steps to ease the crossing of Kosgolla pass. Around the same time the King Dutugemunu had completed the renovation of the stupa at the Mahiyanganaya Rajamaha Viharaya after defeating Elara.
On the day of King Dutugemunu ceremoniously opened the Mahiyangana Stupa after renovations, Bulatha invited the king to see his secret project which was carried out during his free time. He also showed the herculean task of his wife and Queen Viharamahadevi sent her a special invite to the ceremonial opening of the tank by the king.
After ceremony, king Dutugemunu is said to have taken off his royal cape and dressed it on Bulatha making him a general in the army and given him a village called Udathwewa for the contribution he alone has made.
