An island at the southern tip of India
The island is located on the same continental plate as the Indian subcontinent, from which it is separated by the Palk Strait. Adam's Bridge, also called Rama's Bridge, connects Talaimannar, located on Mannar Island, to India, more exactly to Dhanushkodi, near Rameswaram in Tamil Nadu. This natural bridge is actually made of submerged limestone banks, and places Sri Lanka at a distance of 32 km from its Indian neighbor. Unfortunately, it is not possible to connect India to Sri Lanka by boat; the ferry that made the crossing ceased operation in 1984 due to the Sri Lankan conflict. Talks are underway for a resumption of a ferry service between Jaffna and Karaikal, which is part of the territory of Pondicherry.
Relief
The soil of the island is composed of granite, schist and gneiss typical of a basement of the Archean geological period. The layering of the relief has developed over the different eras through the action of erosion and friction of faults, creating the three main parts that constitute the relief of the country: the coastline and plains, the lowlands located at less than 300 m above sea level, and the highlands in the heart of the island.
Most of the island's surface is occupied by plains. The coastline is relatively flat, located on average at 30 meters above sea level. The coasts are bordered by large and beautiful palm-fringed beaches and by lagoons and mangroves inland. The coastal plains cut through the stratification of crystalline rocks in the northeast and southwest of the island, with rocky cliffs, wide bays and small offshore islands. These favorable conditions allowed the emergence of two important ports in Sri Lanka's history: Trincomalee, one of the largest natural ports in the world, and Galle.
The lowlands, with an altitude of less than 300 m, have a low relief, suitable for agriculture. The rocks made of gneiss are more sensitive to erosion.
The mountainous highlands in the center of the island, the Highlands, include the Knuckles Mountains, Horton Plains National Park, the Rakwana Hills in the south, and the country's highest peak, Mount Pidurutalagala (or Mount Pedro) in Nuwara Eliya, which rises to 2,524 m. Other important peaks include Kirigalpotta at 2,392 m and Thotupola which reaches 2,350 m. Sri Pada (Adam's Peak), the most sacred peak of the island, is 2,243 m high and is a godsend.
Hydrography
The rains and monsoons punctuate the life of the islanders and strongly influence the vegetation of the regions. The wet zone in the southwest, which receives the most rainfall, has a green landscape throughout the year. The plains of the dry zone, in the north, east and south, have an arid landscape, with brown soil and small dry shrubs. The landscapes turn green with the arrival of the light monsoon and near the rivers. The rivers of the island have their source in the high mountainous plateaus before flowing towards the plains and the ocean. The most important rivers are the Mahaweli Ganga (335 km) and the Malvathu River (170 km). In the highlands, river courses are frequently altered by changes in terrain, and many waterfalls have eroded a passage at rocky escarpment points. Sri Lanka has more than 50 waterfalls, mostly located in the Highlands. The rivers slow down once they cross the mountainous areas and meander through the flood plains and deltas.
Huge hydraulic works were carried out in the early period of the Anuradhapura kingdom, in order to compensate for the lack of water during the dry seasons. Numerous reservoirs (wewa) were thus created, including the Nuwara Wewa, the Tissa Wewa and the Minneriya Wewa. These artificial lakes were used for land irrigation and were incorporated into a large network of canals a little later. The arrival of the settlers allowed the improvement of the hydraulic system of the country. In the 18th century, the Dutch built hundreds of kilometers of waterways in the western part of the island, which can still be navigated by boat today, especially on the Negombo side. Finally, the Mahaweli Development Project, initiated in 1961 by the Sri Lankan government, is the last major water project in the country. The objective was to rehabilitate and irrigate the surroundings of the Mahaweli River; it allowed the construction of eight dams in order to create large reservoirs, the most famous being those of Victoria, Maduru Oya and Rantambe. The works lasted from 1970 to 2018, when the last dam, Moragahakanda, was completed.
Negative human influence and deforestation
For a long time, the forest occupied almost all the surface of the island, but the introduction of food crops at the end of the 18th century marked the beginning of massive deforestation. The cultivation of rice began at the time of the kingdom of Kandy, which led to the clearing of many hills of medium altitude in order to transform them into arable land. But it is especially the arrival of the British in the 19th century that greatly contributed to change the landscape of the island. In 1815, they introduced the cultivation of coffee, which was fatal for the forests of the center. Soon after, all the coffee plantations were infected by a parasite and were reduced to nothing. The British then replaced coffee cultivation with tea cultivation. Tea plantations developed in the country on a large scale, which resulted in the disappearance of forests and accelerated erosion. As a result, forests covered only about 50% of the island's surface by the 1950s. During the civil war, the intensive use of roasted palm trees, a species that was very present in the north of the island, and the bombings, decimated a large part of the remaining forests. Today, the forest areas constitute only 20% of the country's surface and are mainly present in the southwestern interior. To counter this deforestation phenomenon and to try to preserve the flora and fauna of the country, the government has created a large number of protected areas, sanctuaries and national parks.
