Man-made wetlands

Consist of three groups and nine different wetland types. With a unique and ancient hydrological civilization, the country is dotted with a large number of man-made water bodies referred to as "wewas". It is said that Sri Lanka probably has the highest number of man-made water bodies in the world with an estimated total of more than 10,000 wewas countrywide. Linked to these tanks are many kilometers of canal systems, thousands of hectares of paddy fields

MAN MADE WETLANDS

GEOTHERMAL	AQUACULTURAL	AGRICULTURAL	INDUSTRIAL/URBAN
Geothermal wetlands	Fish / shrimp ponds	Farm / small tanks	Saltpans
		irrigated land	Reservoirs / barrages
		Seasonal flooded fields	Gravel / brick / clay pits
			Sewage / treatment ponds
			Canals

MAN-MADE WETLANDS Some of the major types are described below:-

Tanks and Reservoirs:

Although there are no natural lakes in Sri Lanka, an array of ancient irrigation tanks has substituted the former wetland type. Numbering nearly 10,000, these man-made wetlands depict the rich cultural heritage of Sri Lanka. The major irrigation reservoirs (each more than 200 ha) cover an area of 7820 ha, while the seasonal/minor irrigation tanks (each less than 200 ha) account for 52250 ha. Typical ancient irrigation tanks include the Parakrama Samudraya and the Minneriya tank.

Rice Fields:

Rice fields are characterized by the presence of a standing water body, which is temporary and seasonal. Hence, flooded rice fields can be considered agronomically managed marshes. They are temporary and seasonal aquatic habitats, managed with a variable degree of intensity. The total area under rice cultivation at present is about 780,000 ha (approximately 12% of the total land area), which is distributed over all the agro-ecological regions except for areas located at very high elevation. Approximately 75% of rice lands in Sri Lanka are located within inland valley systems of varying form and size while the rest are found in alluvial plains and also on terraced uplands in the interior.