Sri Lanka - Geography

Geography

Sri Lanka lies on the Indian tectonic plate, a minor plate within the Indo-Australian Plate. It is in the Indian Ocean southwest of the Bay of Bengal, between latitudes 5° and 10°N, and longitudes 79° and 82°E. Sri Lanka is separated from the Indian subcontinent by the Gulf of Mannar and the Palk Strait. According to the Hindu mythology, a land bridge existed between the Indian mainland and Sri Lanka. It now amounts to only a chain of limestone shoals remaining above sea level. It was reportedly passable on foot up to 1480 AD, until cyclones deepened the channel.

The island consists mostly of flat-to-rolling coastal plains, with mountains rising only in the south-central part. The highest point Pidurutalagala, reaching 2,524 metres (8,281 ft) above sea level. The climate is tropical and warm, due to the moderating effects of ocean winds. Mean temperature ranges from 17 °C (62.6 °F) in the central highlands, where frost may occur for several days in the winter, to a maximum of 33 °C (91.4 °F) in other low-altitude areas. Average yearly temperature ranges from 28 °C (82.4 °F) to nearly 31 °C (87.8 °F). Day and night temperatures may vary by 14 °C (57.2 °F) to 18 °C (64.4 °F).

Rainfall pattern is influenced by monsoon winds from the Indian Ocean and Bay of Bengal. The "wet zone" and some of the windward slopes of the central highlands receive up to 2,500 millimetres (98.4 in) of rain each month, but the leeward slopes in the east and northeast receive little rain. Most of the east, southeast, and northern parts of the country comprise the "dry zone", which receives between 1,200 mm (47 in) and 1,900 mm (75 in) of rain annually. The arid northwest and southeast coasts receive the least amount of rain at 800 mm (31 in) to 1,200 mm (47 in) per year. Periodic squalls occur and sometimes tropical cyclones bring overcast skies and rains to the southwest, northeast, and eastern parts of the island. Humidity is typically higher in the southwest and mountainous areas and depends on the seasonal patterns of rainfall.

The longest of the 103 rivers in the country is Mahaweli River, covering 335 kilometres (208 mi). These waterways give rise to 51 natural waterfalls of 10 meters or more. The highest is Bambarakanda Falls, with a height of 263 metres (863 ft). Sri Lanka's coastline is 1,585 km long. It claims an Exclusive Economic Zone (EEZ) extending 200 nautical miles, approximately 6.7 times the country's land area. The coastline and adjacent waters support highly productive marine ecosystems such as fringing coral reefs, shallow beds of coastal and estuarine seagrasses. Sri Lanka inherits 45 estuaries and 40 lagoons too. Country's mangrove ecosystem which spans over 7,000 hectares, played a vital role in buffering the force in the waves of 2004 Indian Ocean tsunami. The island is rich with minerals such as Ilmenite, Feldspar, Graphite, Silica, Kaolin, Mica and Thorium. Existence of Petroleum in the Gulf of Mannar has also been confirmed and extraction attempts are underway.