“Not a single drop of water received from rain should be allowed to flow into the sea without making any use of it”

– King Parakramabahu

Sri Lanka is a country with a rich heritage that amazes the world. Starting from culture, arts and crafts, architecture and designing to ancient knowledge on various fields, the island’s glory had been extended to numerous parts of the world. One such wonder in Sri Lanka is the irrigation system and the water technology that has been deployed in constructing tanks, canals and Dams. Tanks, especially is a wonder, given that it is constructed with much attention even to the subtle aspects of its longevity and protection. Several teams of researches, during different times, have visited Sri Lanka from foreign countries, to study the astounding technology that has been acquired in construction of tanks.

The inception of tanks

The first remarks about constructing tanks in Sri Lanka are found long back then, before the era of the Christ. It is largely and directly connected with the activities of the people who lived in the early settlements which were established mostly in the dry zone. Since their need of water escalated with the expansion of population and basic needs (i.e. air, water, food, shelter) grew into complex needs, people wanted more water. Yet, the dry zone was not the home for as many rivers and other water bodies as the wet zone. Therefore, people who lived in the dry zone started to accumulate water by constructing a dam or an anicut across water-flow. Also, when there had been a low land surrounded by high lands in three sides, they had constructed a dam across the other side and made it able to contain water when it rains. As it was not a hard toil, only a little man-power was required. Thus, small group of villagers had been able to finish constructing a tank easily. These are called small-scale tanks

According to Mahavansa -the written record of the country’s history- speaks of three tanks named Jayavapi, Abhayavapi (known as Basawakkaluma at present) and Gaminivapi which had been constructed during the period of King Pandukabhaya. It also records about the Thissawewa of Anuradhapura, which is considered to have been constructed by king Devanampiyatissa.

Small got bigger

However when the society experienced a rapid expansion of population, the contemporary small tanks couldn’t serve the growing demand for water. Thus people had to go for ‘bigger’ options like constructing large scale tanks to accumulate more water.

The first recorded construction of large tanks is credited to the account of King Vasabha (67- 111CE). Sri Lankans had acquired much knowledge and experience in constructing tanks and thus the king only had to gather that knowledge and develop it to fit a large scale project. It is chronicled in the history that he constructed 11 large tanks including Mayethwewa (now Mahavilachchiya), and Maanikviti (Maanakattiya at present).

King Mahasen is another great figure in history, who constructed numerous large tanks including famous Minneriya. Huruluwewa and Mahakanadara Wewa are other two tanks done by him. King Dathusena and King Parakramabahu, are also to be added to the list of kings who ameliorated the water technology in Sri Lanka by constructing massive tanks.

Quite a challenge

Constructing a large tank of many acres of area hasn’t ever been an easy task. There had been various challenges to be met during the process. Above all, a fine place had to be chosen wisely to retain water. It had been considered if the ground has its own springs or any flow of water running through.

Of course, a large tank withholds a huge amount of water which in fact creates a massive pressure on the walls of the tank. Also, a lot of people had been living in the under stream areas of the tank. So, the walls of the tank had to be very strong and firm, lest villages of people could have been drowned. Hence, as a strategy, people had been keen to select a low ground surrounded by highlands or two mountains especially to construct a tank. On the other side also, the wall had been built with several layers of soil, clay and stones in a special way so that it could cope the pressure generated by water on it.

Apart from those main challenges, there were other challenging tasks to be given attention, such as maintaining the proper water level, distributing water to farm lands and villages, cleaning the tank and so on. Nonetheless, people had come up with various beautiful techniques and devices to overcome those challenges efficiently. Therefore, these huge tanks have been there over so many years since their construction up to this day, while benefitting thousands and millions of Sri Lankans.

We will discuss further the special technical aspects of a tank in Teen Inc articles in the weeks to come.

By Induwara Athapattu