From the middle of the Anuradhapura Kingdom to the Polonnaruwa Kingdom (1017-1236) the technology of building reservoirs in Sri Lanka was at its peak and it was during this period that most of the largest reservoirs in the country were built. Other large reservoirs such as Lake Minneriya and Lake Kaudulla belong to the 3rd century. Lake Minneriya was built by King Mahasen (276-303), the builder of the great reservoirs that ruled Anuradhapura. The reservoir is located on 4670 acres and is a 13-meter high dam that stretches for 2 km. The water arrived from Mahaveli River, 48 km away, along the Elahara canal built by King Vasabha (65-109) before his time.
The waters of this reservoir greatly changed the landscape of Minneriya, and when Mahasen passed away, the people of Mineria made him known as the Goddess Minneriya or the Goddess Mahasen, and a shrine dedicated to him still stands on the Minneriya Dam. Lake Minneriya provides a valuable service to the people of the dry zone in the Central Province. Lake Minneriya is the source of water for drinking and cultivation. It also acts as a major source of flood trapping in the area.
Minneriya and the surrounding area belong to the dry zone of Sri Lanka, and the whole region receives rains only a limited number of days from April to November (parallel to the northeast monsoon), the rest of the year there is no rain and most of the water resources dry up. Due to this weather pattern, Mineria and the surrounding area experience a long dry season each year, and Lake Minneriya helps people when there is a shortage of water during the dry season. Due to the large area of soft-growing grassland, people can be positioned from a very good angle of view and have a wide-angle when looking for wildlife. The main reason for a large number of elephants to gather around the lake. The grass around the lake attracts not only wild elephants from the Minneriya National Park but also wild elephants such as the nearby Wildlife Sanctuary Kaudulla and Eco Sri Lanka.