Eastern vs Western Ghats: Key Geographical Differences Explained for UPSC SSC

Geographical Location and Extent

The Western Ghats, also known as Sahyadri, form a continuous mountain range along the western coast of India. They stretch for approximately 1,600 kilometers from the Tapi River valley in the north, through Gujarat, Maharashtra, Goa, Karnataka, Kerala, and Tamil Nadu, ending at Kanyakumari. This range acts as a significant barrier to the monsoon winds originating from the Arabian Sea. The average elevation of the Western Ghats is around 1,200 meters, with peaks exceeding 2,000 meters.

In contrast, the Eastern Ghats are a discontinuous chain of mountains along India's eastern coast. They run roughly parallel to the Bay of Bengal, extending from Odisha in the north, through Andhra Pradesh, to Tamil Nadu in the south. The Eastern Ghats are much older and more eroded than the Western Ghats, resulting in a lower average elevation, typically around 600 meters. They are broken by several major rivers, including the Mahanadi, Godavari, Krishna, and Kaveri, which flow eastward into the Bay of Bengal.

Topography and Elevation

The Western Ghats are characterized by their steep, escarpment-like western slopes and gentler eastern slopes. This dramatic relief is due to their formation as a fault-block mountain range during the break-up of the Gondwana supercontinent. The highest peak in the Western Ghats, and indeed in Peninsular India, is Anamudi, located in Kerala, with an elevation of 2,695 meters. Other prominent peaks include Doddabetta (2,637 meters) in the Nilgiri Hills and Kalsubai (1,646 meters) in Maharashtra.

The Eastern Ghats, being older and more weathered, exhibit a more subdued and dissected topography. They consist of a series of detached hills and plateaus rather than a continuous range. The highest peak in the Eastern Ghats is generally considered to be Jindhagada Peak (1,690 meters) in Andhra Pradesh, though some sources also mention Arma Konda (1,680 meters) or Mahendragiri (1,501 meters) in Odisha. The numerous river valleys have carved out significant gaps, making travel and connectivity easier across the Eastern Ghats compared to the Western Ghats.

Climate and Rainfall

The Western Ghats play a crucial role in India's monsoon climate. Their high elevation and orientation perpendicular to the southwest monsoon winds cause significant orographic rainfall on their western windward slopes. Areas like Mahabaleshwar and Agumbe receive extremely high annual rainfall, often exceeding 7,000 mm. The eastern leeward side of the Western Ghats, however, lies in a rain shadow region, experiencing much lower rainfall and semi-arid conditions.

The Eastern Ghats receive comparatively less rainfall from the southwest monsoon due to their lower elevation and discontinuous nature. They are also parallel to the monsoon winds, reducing the orographic effect. However, the Eastern Ghats receive rainfall from the retreating monsoon (northeast monsoon) and tropical cyclones originating in the Bay of Bengal, particularly in the southern parts like Tamil Nadu. This leads to a different rainfall pattern, with a significant portion of precipitation occurring during the post-monsoon season.

Biodiversity and Ecosystems

The Western Ghats are recognized as one of the world's eight 'hottest hotspots' of biological diversity. They are home to an extraordinary array of flora and fauna, many of which are endemic, meaning they are found nowhere else on Earth. This region includes diverse ecosystems such as tropical evergreen forests, moist deciduous forests, montane grasslands, and shola forests. The high biodiversity has led to its designation as a UNESCO World Heritage Site in 2012, encompassing 39 properties across seven states. Notable species include the Nilgiri Tahr, Lion-tailed Macaque, and various species of amphibians and reptiles.

The Eastern Ghats, while less biodiverse than their western counterparts, still support significant ecological value. They feature dry deciduous forests, moist deciduous forests, and scrub jungles. The biodiversity here is also under threat from deforestation, mining, and agricultural expansion. Important wildlife corridors exist, connecting various protected areas. The Eastern Ghats are known for species like the Indian Giant Squirrel, Four-horned Antelope, and various bird species. The region also holds significant tribal populations, whose livelihoods are closely intertwined with the forest ecosystems.

Important Keywords Explained

Orographic Rainfallconcept

Orographic rainfall occurs when moist air is forced to rise over a mountain barrier. As the air ascends, it cools, condenses, and forms clouds, leading to precipitation on the windward side of the mountain. The leeward side, in contrast, experiences a rain shadow effect, receiving much less rainfall. This phenomenon is a key characteristic of the Western Ghats' climate.

Biodiversity Hotspotconcept

A biodiversity hotspot is a biogeographic region with significant levels of biodiversity that is also threatened by human habitation. To qualify as a hotspot, an area must contain at least 1,500 species of vascular plants as endemics and have lost at least 70% of its primary vegetation. The Western Ghats meet these criteria, making them a critical area for conservation.

Anamudiplace

Anamudi is the highest peak in the Western Ghats and the highest point in South India, with an elevation of 2,695 meters (8,842 feet). It is located in the Idukki district of Kerala, within the Eravikulam National Park. The name 'Anamudi' literally means 'elephant's forehead' in Malayalam, referring to its resemblance to an elephant's head.

Additional Facts & Context

• The Western Ghats were declared a UNESCO World Heritage Site in 2012.
• The average elevation of the Western Ghats is approximately 1,200 meters.
• The average elevation of the Eastern Ghats is approximately 600 meters.
• The Western Ghats span six Indian states: Gujarat, Maharashtra, Goa, Karnataka, Kerala, and Tamil Nadu.
• The Eastern Ghats span four Indian states: Odisha, Andhra Pradesh, Telangana, and Tamil Nadu.