Three zones can be distinguished based on the elevation: The coastal belt, the plains and the central highlands (Figure 1). Most of the island's surface consists of plains between 30 and 300 meters above sea level is the coastal belt. Much of the coast consists of scenic sandy beaches indented by coastal lagoons. In the Jaffna Peninsula, limestone beds are exposed to the waves as low-lying cliffs in a few places. In the northeast and the southwest, where the coast cuts across the stratification of the crystalline rocks, rocky cliffs, bays, and offshore islands can be found; these conditions have created one of the world's best natural harbors at Trincomalee on the northeast coast, and a smaller rock harbor at Galle on the southwestern coast.

Most of the island's surface consists of plains between 30 and 300 meters above sea level. The erosion remnants are present throughout the north central part of the plains. Extensive erosion in this area has worn down the ridges and deposited rich soil for agriculture downstream. In the southeast, a red, lateritic soil covers relatively level ground that is studded with bare, monolithic hills.

In the southwest, ridges and valleys rise gradually to merge with the Central Highlands, above 300 m, giving a dissected appearance to the plain.

Rivers in Sri Lanka rise in the Central Highlands and flow in a radial pattern toward the sea passing all three topographic zones. Most of these rivers flow towards southern and southwestern coast are short. There are sixteen principal rivers which are longer than 100 kilometers in length, with twelve of them carrying about 75 percent of the mean river discharge in the entire country. The longest rivers are the Mahaweli Ganga (335 kilometers). In the highlands, river courses are frequently broken by discontinuities in the terrain, and where they encounter escarpments, numerous waterfalls and rapids have eroded a passage. Once they reach the plain, the rivers slow down and the waters meander across flood plains and deltas. The upper reaches of the rivers are wild, and the lower reaches are succesptible to seasonal flooding.

Physiogrphy

Climate