Ancient irrigation...

It was during the reign of king Mahasen that some of ancient Sri Lanka's greatest irrigation developments took place. Especially building of the Minneriya tank and other irrigational developments done by King Mahasen elevated him to the rank of God in Sri Lankan folk history. Development in the agricultural systems was a Priority of the kings of the Anuradhapura dynasty even more so than centuries before. The building of great Stupas, monasteries, palaces, and other Public Work entailed the need for a large labor force which had to be supported by good harvests and an agricultural surplus.

The dry zone of Sri Lanka where the first settlement was made required a constant water supply although the land itself was more suitable for the cultivation of rice.

At the beginning of the Anuradhapura Kingdom tanks were built mainly as water storage tanks. But with time the need arose for a water supply that could withstand the uncertainties of the monsoon rains. The ancient Sri Lankans gradually developed an Irrigation system using hydraulic engineering methods which would support a thriving agricultural and growing population. It is said that King Mahassen built 16 great tanks, he also diverted the water from the Mahaweli River and the Amban river and initiated a permanent water supply for the Minneriya tank. The North-Western regions of the island were made self-sufficient through a policy of water conservation.

The ancient Sri Lankans can be credited with the innovation of the valve pit or sluice gate which could regulate the flow of water from a reservoir to low-lying agricultural fields and villages. One of the oldest sluice gate in the history of irrigation was discovered when modern engineers began construction work in the late 20th century, Once they did all the modern testing and readings and decided that this was the best place for a sluice gate they started to the necessary preparations, and to their astonishment found that the same was constructed there over 2000 years ago at the exact location.

Just as the 2500-year-old Buddhist monuments and temples remain as the main part of the living culture of the Sri Lankans the irrigational systems of the past are an integral part of the present-day agricultural activity of the country.

The construction of the great Minneriya Tank also opened up the Eastern lands of the great Mahaweli river, and its close proximity to the ancient port of Gokanna or present-day Trincomalee helped develop ancient trade. It was the beginning of great commerce activities between then Sri Lanka, China, and Southeast Asia.

The irrigational developments that the ancient Sri Lankans were able to accomplish helped them to intensify great development in agriculture which continued throughout the late history of the island.