Executive Summary
Sri Lanka is an island nation in the Indian Ocean, located about SO km to the southeast of the Indian sub-continent. It comprises a mainland of area 55,610 km and a large number ofsrnall islands with only six having area more tha n 1,000 ha located off the northwest coast. The south-central part of the country is mountainous, while the rest of the country is mostly flat undulating land. The country has a coast line of about 1,585 km, comprising sandy beaches and sand dunes, and dotted with many lagoons, estuaries, marshes, mangroves and deltas. There are altogether 103 rivers spread around the country, with a total annual run-offof about 43 Grn.
The climate of the country depends largely on the monsoon wind pattern. The annual mean surface temperature has an average of about 27°C in the lowlands and an annual mean temperature of about 15°C in the highlands. Based on the annual rainfall received, the country is divided In to three climatic zones - wet-, intermediate- and dry-zone _ The wet-zone covering approximately the south-western quadrant, receives an annual rainfall in the range 2,500 - over 5,000 mm, while the dry-zone covering the north, eastern and most parts of the north-central provinces receives an annual rainfall below 1,750 mm. The intermediate-zone lying between the wet- and dry - zones receives annually rainfall between 1750 and 2500 mm. The southwest monsoon winds bring rainfall mainly to the wet-zone, while the northeast monsoon brings rainfall mainly to the dry- and intermediate- zones. The two inter-monsoon periods bring rain spread over the entire country.