Sri Lanka has 103 rivers. The longest of these is the Mahaweli River, extending . These waterways give rise to 51 natural waterfalls of  or more. The highest is Bambarakanda Falls, with a height of . Sri Lanka's coastline is  long. Sri Lanka claims an exclusive economic zone extending 200 nautical miles, which is approximately 6.7 times Sri Lanka's land area. The coastline and adjacent waters support highly productive marine ecosystems such as fringing coral reefs and shallow beds of coastal and estuarine seagrasses.