Sri Lanka

Area equipped for irrigation increased from 457 200 ha in year 1980 to 570 000 ha in year 1995 and was assumed to be constant at this level until year 2011 [LK01]. Subnational information on total area equipped for irrigation was not available. Area equipped for irrigation was estimated therefore at the division level based on the irrigated paddy land extracted from an inventory related to year 2010 [LK02] and an inventory of irrigated land for crops different from paddy rice for each district related to season 1990-1991 [LK03]. Total irrigated paddy rice area was 556 630 ha while the area of other irrigated field crops was 60 916 ha in season 1990-1991 and then scaled to the area of 44 100 ha reported for year 2006. Total area equipped for irrigation estimated this way was 600 730 ha. The irrigated area by district is visible in the table below and the irirgtaed area both by district and by division can be downloaded as Sri Lanka irrigation areas in PDF or Sri Lanka irrigation areas in Excel (two sheets).

The locations of 308 major irrigation schemes (more than 40 ha) and 12 lift-irrigation schemes covering 246 700 ha in total were digitized from an irrigation map [LK04]. The rest of the irrigated area was assigned to paddy areas as digitized from a land-use map [LK05], from another map with a higher resolution but dating from 1972 [LK06], and from a map that was part of the 1976 Water Resources Development Plan [LK07]. In divisions where area equipped for irrigation was larger than the sum of area in the registered irrigation schemes and the digitized paddy fields, the remaining difference was assigned to pixels classified as cropland by Globcover regional landcover classification for Central Asia [LK08].

Area equipped for irrigation with groundwater was computed based on statistics on the use of agrowells collected by the agricultural census 2002 [LK09] (Department of Census and Statistics, 2009). It was assumed that the maximum of area irrigated by agrowells in the Maha 2001/02 and the Yala 2002 seasons reported for each district represented the area irrigated with groundwater (6 828 ha in total). Area actually irrigated was 462 500 ha in year 2006 but subnational information on areas actually irrigated was not available.

References

[LK01]: FAO. 2013. AQUASTAT Country Statistics.
[LK02]: Department of Census and Statistics - Sri Lanka. 2013. District Statistical Handbook 2011. http://www.statistics.gov.lk/DistrictStatHBook.asp, 06/03/2013.
[LK03]: Jayewardene, J., Jayasinghe, A. & Dayaratne, P.W.C. 1991. Promoting crop diversification in rice-based irrigation systems. In S.M. Miranda & A.R. Maglinao, eds. Proc. second progress review and coordination workshop of the Research Network on Irrigation Management for Crop Diversification in Rice-Based Systems (IMCD) held in Yogyakarta, Indonesia from 09 to 12 September 1991.
[LK04]: Survey Department. 1988. The national atlas of Sri Lanka. Map ‘Irrigation schemes’. Colombo.
[LK05]: Survey Department. 1988. The national atlas of Sri Lanka. Map ‘Paddy’. Colombo.
[LK06]: Unknown. 1972. Sri Lanka - land use, 1:1,000,000. Map available in the library of the Land and Water Development Division of FAO.
[LK07]: Unknown. 1976. Sri Lanka - water resources development plan. Map available in the library of the Land and Water Development Division of FAO.
[LK08]: ESA. 2008. Regional Globcover Land Cover – Central Asia. Version 2.2. http://postel.mediasfrance.org/en/DOWNLOAD/, 24/03/2009.
[LK09]: Department of Census and Statistics. 2009. Census of Agriculture 2002. Agriculture and Environment Statistics Division, Department of Census and Statistics, Colombo, Sri Lanka, http://www.statistics.gov.lk/agriculture/AGC2002/Location/TabL\_10.htm, 27/08/2009.