Eastern vs Western Ghats: A Comparative Study for UPSC SSC

Geographical Location and Extent

The Western Ghats, also known as Sahyadri, run parallel to the western coast of India. They stretch for approximately 1,600 kilometers from the Tapti River valley in Gujarat, through Maharashtra, Goa, Karnataka, Kerala, and Tamil Nadu, ending at Kanyakumari. This range is continuous and acts as a significant watershed. In contrast, the Eastern Ghats run parallel to the eastern coast of India, from Odisha in the north, through Andhra Pradesh, to Tamil Nadu in the south. They are a discontinuous range, broken by major rivers like the Godavari, Krishna, Mahanadi, and Kaveri, which flow into the Bay of Bengal. The average elevation of the Western Ghats is higher than that of the Eastern Ghats.

Topography and Elevation

The Western Ghats are generally higher and more continuous than their eastern counterparts. Their average elevation is around 1,200 meters, with several peaks exceeding 2,000 meters. Anamudi, located in Kerala, is the highest peak in the Western Ghats and also in Peninsular India, standing at 2,695 meters. Other prominent peaks include Doddabetta (2,637 meters) in the Nilgiri Hills. The Eastern Ghats, on the other hand, have an average elevation of about 600 meters. Mahendragiri, in Odisha, is one of the highest peaks in the Eastern Ghats, with an elevation of 1,501 meters. The discontinuous nature of the Eastern Ghats is due to the erosional activity of the eastward-flowing rivers.

Rivers and Drainage

The Western Ghats form the main water divide of Peninsular India. Most of the major rivers of Peninsular India, such as the Godavari, Krishna, and Kaveri, originate in the Western Ghats and flow eastward into the Bay of Bengal. These rivers create large deltas on the eastern coast. Shorter, swift-flowing rivers like the Periyar and Netravati also originate in the Western Ghats but flow westward into the Arabian Sea. The Eastern Ghats are dissected by these major eastward-flowing rivers, which have carved out broad valleys and gaps. This dissection contributes to the fragmented nature of the Eastern Ghats, unlike the more uniform Western Ghats.

Climate and Biodiversity

The Western Ghats experience a tropical monsoon climate, characterized by heavy rainfall, especially on their western windward slopes, due to the obstruction of the southwest monsoon winds. This high rainfall supports dense evergreen and semi-evergreen forests. The region is recognized as one of the world's eight 'hottest hotspots' of biological diversity, housing a significant percentage of India's plant and animal species. It is a UNESCO World Heritage Site. The Eastern Ghats receive comparatively less rainfall, primarily from the northeast monsoon and cyclonic depressions. Their vegetation is typically dry deciduous, with some moist deciduous patches. While less biodiverse than the Western Ghats, they still support unique ecosystems and wildlife, including several endemic species.

Geological Formation and Resources

The Western Ghats are believed to have formed during the break-up of the supercontinent Gondwana, approximately 150 million years ago. They are primarily composed of ancient Precambrian rocks, including gneisses, charnockites, and granite. This geological history has resulted in rich mineral deposits, though extraction is often restricted due to environmental concerns. The Eastern Ghats are older than the Western Ghats and are composed of a variety of rocks, including khondalites, charnockites, and granite gneisses. They are known for deposits of bauxite, manganese, and iron ore. Both ranges are vital for their forest resources, including timber and non-timber forest products, and play a crucial role in regulating regional climate and water cycles.

Important Keywords Explained

Biodiversity Hotspotconcept

A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is under threat from humans. To qualify as a hotspot, a region must contain at least 1,500 species of vascular plants as endemics (meaning they are found nowhere else on Earth) and have lost at least 70% of its primary vegetation. The Western Ghats meet these criteria, making them a critical area for conservation.

Gondwanaconcept

Gondwana was a supercontinent that existed from the Neoproterozoic (about 550 million years ago) until the Jurassic (about 180 million years ago). It was formed by the accretion of several cratons and included most of the landmasses in today's Southern Hemisphere, including Antarctica, South America, Africa, Madagascar, Australia, and the Arabian Peninsula and the Indian subcontinent. The geological formation of the Western Ghats is linked to the break-up of Gondwana.

Monsoonconcept

Monsoon refers to a seasonal reversal of wind direction, accompanied by corresponding changes in precipitation. In India, the Southwest Monsoon (June-September) brings heavy rainfall to much of the country, particularly the Western Ghats. The Northeast Monsoon (October-December) affects the southeastern coast, including parts of the Eastern Ghats, bringing winter rainfall.

Additional Facts & Context

• The Western Ghats cover an area of approximately 160,000 square kilometers.
• Around 30% of India's plant species are found in the Western Ghats.
• The Western Ghats are home to at least 325 globally threatened species.
• The Eastern Ghats are older than the Western Ghats, with some rock formations dating back 2.5 billion years.
• The Palghat Gap, a significant break in the Western Ghats, is about 30 km wide.