Biso Kotuwa - Irrigation inventions of old srilanka

"Sinhalese have the Finest & Greatest reservoirs in the world"

-said British Archaeologists 1700 years later when they discovered the perfection of the irrigation network in 130 AD.

 
Once the Sinhalese King told the technology graduates, "There is nothing in this world that people of energy cannot achieve". And the following year Sinhalese had the World's Best Irrigation network, and the foreigners call Sri Lanka "The Granary of Asia".

Sinhalese irrigation network turbo-charged in to a vast, sophisticated network around 375 BC, with the arrival of the North Indian migrants who were relatives of the Buddha's family from the North Indian Maha Janapadas. The network was repeatedly destroyed during the 30 invasions and the dozens of ethnic rebellions. Each time the hard working Sinhalese repaired them. The British finally destroyed the network in 1848 AD. 

1155 AD- World's Best Irrigation Network :

This is regarded as the peak of the Sinhalese Hydraulic engineering. Over 5000 lakes and reservoirs were interlocked in a network of 4000 canals. Almost all villages in the country were supplied with enough water to irrigate all paddy fields. Village chiefs were placed in charge of the maintenance of the system. The entire world hasn't seen such a delicate system. Not even the much-publicized networks in North India and in Burma, could match the sustained and the methodical thoroughness of the development in Lanka at this time. 

Secret of the Biso Kotuwa :

Bisokotuwa is inside the Dam. The water from the reservoir flows into the Bisokotuwa with very high pressure through strong tubes made of stone. These tubes are generally 2-4 feet wide.

The bottom 2-6 feet of the Bisokotuwa, into which the high pressure water flows in, is generally made of Stone. The top is generally made of high quality bricks, about one feet large, strong enough to withstand the relatively low pressure water at the top. 

While the water is forced to move upwards inside the Bisokotuwa, the pressure reduces. Then the water exits the Bisokotuwa through 2 or 3 stone tubes. Generally, this water is directed to a second Bisokotuwa, where the same process is repeated further reducing the water pressure.

Finally the water, unbelievably disciplined and calm, flows out through a larger tube to the outside of the Dam. This tube is normally 6 feet wide at the beginning and then widens to about 14 feet at the exit point of the Dam. That reduces the water pressure further.

This was an outstanding idea, which was based on precise mathematics. Such were the skills, and the talents of the Sinhalese engineers. 

It can’t be said that we have found enough of ancient irrigation works around the great buried cities. Yet it leads to a higher estimate of the state of enlightenment of the old Sinhalese than that of all their works "- R.L.Brohier


1155 AD- Highest number of irrigation works done by a Lankan King :

King Parakramabahu built 1470 reservoirs. That number remains a record in the Lankan history. He enlarged 53 reservoirs in Dakkinadesa alone. He repaired 165 dams, 3910 canals, 163 major reservoirs, and 2376 mini reservoirs. 

1155 AD- The Granary of Asia :

As the irrigation systems were perfected, the results were outstanding. Lanka became to be known as " The Granary of the Asia "

1155 AD- Export Development Zones :

King Parakramabahu identified areas of economic value and developed them into export-income generating zones. Coastal pearl fishing, Gem mines in Ratnapura, Fertile lands of rice and spices were included in these zones.

just see the remains...you should go and look at them yourself!!!