Rivers and lakes

All rivers of Sri Lanka originate in the central highlands. The longest river of Sri Lanka, the Mahaweli, traverses a course of about 330 km (about 205 mi). The country’s second longest river is the Aravi Aru, traversing about 220 km (about 135 mi) on a northwestward course, from the central highlands to the Gulf of Mannār.

Sri Lanka has no natural lakes. Dams on the Mahaweli and other rivers have created large reservoirs. In addition, a series of small reservoirs called tanks dot the north central plains, storing water during the dry season. Some of the tanks were constructed as many as 2,000 years ago by Kings who built complex irrigation systems.

Sri Lanka's known freshwater species include 90 fish (with twenty-six endemics) and 21 crabs. Ongoing studies suggest that the number of un-described species is potentially quite large.

Other major rivers include

• Malwathu Oya [165 km] Kelaniya River [145 km]
• Yan Oya [142 km]
• Walawe River [137 km]
• Kalu Ganga [129 km]
• Maha Oya [134 km]

The high land ( Hill country) OR World heritage sites