Friday, 3 July 2015

Western Ghats – South Western India

The Western Ghats or Sahyādri runs north to south along the western edge of the Deccan Plateau, and separates the plateau from a narrow coastal plain along the Arabian Sea. The range starts near the border of Gujarat and Maharashtra, south of the Tapti River, and runs approximately 1600 km through the states of Maharashtra, Goa, Karnataka, Tamil Nadu and Kerala ending at Kanyakumari. These hills cover 160,000 km² (roughly 6% of India’s total geographical area) and form the catchment area for complex riverine drainage systems that drain almost 40% of India. The average elevation is around 1,200-1300 metres. Western Ghats are home to 30% of flora and fauna species found in India

Western Ghats are known as Sahyadri in northern Maharashtra, Sahya Parvatam in Kerala and Nilagiri Malai in Tamil Nadu. Western Ghats are home to many hill stations like Matheran, Lonavala-Khandala, Mahabaleshwar, Panchgani, Amboli Ghat, Kudremukh and Kodagu. The extreme northern parts of Western Ghats falls in the Dangs district of Gujarat, known for Dang (Bamboo) forests. The confluence of the Eastern and the Western Ghats is at Biligirirangan Hills in Karnataka. Anamudi 2,695 metres in Kerala the highest peak in Western Ghats. Mullayanagiri is the highest peak in Karnataka 1,950 meters. The smaller ranges of the Western Ghats include the Cardamom Hills and the Nilgiri Hills. Cardamom hills are located in southeast Kerala and southwest Tamil Nadu. They conjoin the Anaimalai Hills to the northwest, the Palni Hills to the northeast and the Agasthyamalai Hills to the south as far as the Ariankavu pass. The crest of the hills forms the boundary between Kerala and Tamil Nadu. Anamudi is also located in Cardamom Hills. The Nilgiri Hills are home to the hill station Ooty. There are many important passes in Western Ghats such as Tamhini Ghat, Palakkad Gap, Naneghat, Kasara ghat etc. The northern portion of the narrow coastal plain between the Western Ghats and the Arabian Sea is known as the Konkan Coast, the central portion is called Kanara and the southern portion is called Malabar region or the Malabar Coast. The foothill region east of the Ghats in Maharashtra is known as Desh, while the eastern foothills of the central Karnataka state is known as Malenadu

Geology :
There are two views regarding the Geology of the Western Ghats. One view says the mountains of the Western Ghats are Block Mountains formed due to the down warping of a part of land into the Arabian Sea. Other view says that the mountains of the Western Ghats are not true mountains, but are the faulted edge of the Deccan Plateau. Major rocks found in the region include Basalt, charnockites, granite gneiss, khondalites, leptynites, metamorphic gneisses with detached occurrences of crystalline limestone, iron ore, dolerites and anorthosites.


The rivers that originate in Western Ghats and flow towards west are Periyar, Bharathappuzha, Netravati, Sharavathi, Mandovi etc. The west flowing rivers of Western Ghats are fast-moving, owing to the short distance travelled and steeper gradient. This makes Western Ghats more useful than Eastern Ghats in terms of production of hydroelectricity. The steep gradient makes the Jog Falls on Shravasthi River in Karnataka as one of the most spectacular waterfalls in India. Narmada and Tapti although don’t rise from Western Ghats but flow westwards. The rivers that originate in Western Ghats and flow towards east include three major rivers viz. Godavari, Krishna and Kaveri, and many smaller / tributary rivers such as Tunga, Bhadra, Bhima, Malaprabha, Ghataprabha, Hemavathi, Kabini. These east flowing rivers are comparatively slower moving and eventually merge into larger rivers such as the Kaveri and Krishna.

In comparison to the eastern side, the western side of the Western Ghats is area of high rainfall because the mountains intercept the rain-bearing westerly monsoon winds. The dense forests also contribute to high orographic precipitation. The climate is humid and tropical in the lower reaches tempered by the proximity to the sea. Elevations of 1,500 m and above in the north and 2,000 m and above in the south have a more temperate climate. Average annual temperature here is around 15 °C. In some parts frost is common, and temperatures touch the freezing point during the winter months. Mean temperature range from 20 °C in the south to 24 °C in the north. It has also been observed that the coldest periods in the south Western Ghats coincide with the wettest. During the monsoon season between June and September, the unbroken Western Ghats chain acts as a barrier to the moisture laden clouds. The heavy, eastward-moving rain-bearing clouds are forced to rise and in the process deposit most of their rain on the windward side. Rainfall in this region averages 3,000–4,000 mm. The eastern region of the Western Ghats which lie in the rain shadow, receive far less rainfall averaging about 1,000 mm bringing the average rainfall figure to 2,500 mm.