Sri Lanka is covered with a network of thousands of man-made lakes and ponds, known locally as 'tanks.' Some are truly massive and inspire modern day engineers. Many are thousands of years old. Reservoirs and canals studded the northern and north-central plains, tapping every source of water.
Based on the storage and use of water for the cultivation of wet fields during previous eras, researchers have stated that the island's early civilization was hydraulic based. The early Indo-Aryan settlers cultivated rice and settled along river valleys and other suitable lands; they began with simple schemes for damming rivers and storing water below them. Each village stored water in reservoirs by tapping seasonal streams, and these ideas were spread throughout the country and became characteristics of every village.
Many kings over the centuries built colossal tanks. King Parakramabahu either built or restored 163 major reservoirs, 2,617 minor tanks, 3,910 irrigation channels, 328 stone sluices and 168 sluice blocks, besides repairing 1,969 breaches in embankments. His Sea of Parakrama is a gigantic work of irrigation that commands admiration even today.
Further technical progress was achieved in the reign of King Mahasena. A number of storage tanks and canals are attributed to him, the most outstanding of which is the Minneriya tank and its feeder canals. The construction and maintenance of large-scale irrigation work became a regular preoccupation of kings.
Irrigation continues to be a major focus of the Sri Lankan government. Dams have been built, artificial lakes have been constructed, and rivers have been diverted to provide water to the people. The main emphasis of the government of Sri Lanka has been on agricultural development through the renovation of ancient irrigation work and resettlement of the landless population in the dry zone.
Objectives of current irrigation systems include:
to increase food production;
to provide land for the landless;
to earn or save on foreign exchange; and
to generate employment and raise the income of the farming community.