Western And Eastern Coastal Plains Of India

India is surrounded by water on three sides with a total sea boundary of 7516 km, including both mainland and island coastline. From the Rann of Kutch in the west to West Bengal in the east, the mainland coastline stretches for around 6,150 km. Nine states (Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh, Odisha, West Bengal) and four union territories (Daman & Diu, Puducherry, Andaman & Nicobar Islands and Lakshadweep Islands) make up India’s coastline. The Arabian Sea runs along the western coastal plains, while the Bay of Bengal runs parallel to the eastern coastal plains. Western coastal plains are submerged plains and provide ideal conditions for the development of ports and harbors while Eastern coastal plains are emerged plains forming long continental shelves which are not suitable for the formation of harbors. At Kanyakumari, the western and eastern coastal plains meet with each other.

Western Coastal Plains

The Western Coastal Plains runs between the west coast of India and the Western Ghats hills and stretches from the Gulf of Khambhat in the north to Kanyakumari in the south measuring 1500km. They are separated into four sections from north to south i.e. Kathiawar and Kutch coast, Konkan coast, Kannada coast and Malabar coast covering the states of Gujarat, Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu. Width of these coastal plains varies, and are narrow in the middle and widen as we move north or south and have an average width of 50 km. Because of the narrow width, rivers flowing in these regions form no delta. Off the coast of Bombay, the West Continental shelf is the widest measuring around 350 km. They are submerged coastal plains and provide ideal conditions for the development of ports and harbors. Some of the important coast are Kandla, Mazagaon, JLN port, Marmagao, Mangalore, Cochin etc. During the southwest monsoon, these plains get a lot of rain from the Western Ghats.

Characteristics of Western Coastal Plains:

• The Arabian Sea on the west and the Western Ghats on the east encircle the western coastal plains.
•  coastal sand dunes, alluvial tracts, mudflats, sand beaches, lagoons, lateritic platforms, estuaries, and residual hills are the prominent features of the Western Coastal Plain.
• Western Coastal Plains are submerged plains and are well adapted for the development of natural harbor.
• There are two gulfs on its northern side: the Gulf of Khambhat and the Gulf of Kutch.
• On western coastal plains, rivers form estuaries, which are great for pisciculture (fishing and fish production).
• These plains receives heavy rainfall during the southwest monsoon.

Western Coastal Plains are divided into Four Parts:

A. Kathiawar and Kutch Coast: 

The Kutch Peninsula was an island surrounded by oceans and lagoons. The material brought by the Indus River, which used to flow through this area, filled these seas and lagoons and formed it as an integral part of coastal plains. To the south of the Kutch is the Kathiawar Peninsula, which is home to Gir range. It is famous for the Gir lion and is surrounded by lush forests. The Tapti, Narmada, Sabarmati, and Mahi rivers all deposit large amounts of sediment in the Gulf of Cambay, forming estuaries. Kutch region is famous for the large scale production of salt. 

B. Konkan Coast: 

Konkan plains lie between Daman and Goa. It is a rocky and uneven terrain and  encompasses the southern beaches of Gujarat, Maharashtra and Goa. Kashid beach, Murud beach, Juhu beach, Versova beach, Manori beach, Alibaug beach, and Harihareshwar beach are most prominent Konkan beaches. The Konkan coast is home to India’s major oil fields, Mumbai High oilfield located 170 km away from the Konkan Coast.

C. Kannada Coast: 

Kannada coast runs between Madgaon and Mangalore. The plain is narrow, with a maximum width of 70 km near Mangalore, and an average width of 30-50 km. Streams that originate in the Western Ghats sometimes down steep hillsides and form waterfalls. The Sharavati creates a magnificent waterfall known as Jog Falls, which is 271 meters high. 

D. Malabar Coast: 

The Malabar coast is the southernmost section of India’s western coastal lowlands and runs between Mangalore and Kanyakumari. It is more than 500 km long and has a breadth ranging from 40 to 80 km. The Kerala Coast is known for its lakes, backwaters, lagoons, spits, and other natural features. The Vembanad Lake in Kerala is India’s longest lake and located on the Kerala coast. Ashtamudi lake and Sasthamcotta lake are the other two popular lakes.

Eastern Coastal Plains:

The Eastern Coastal Plains stretches from the Subarnarekha river in the north to Kanyakumari in the south with an average width of 100 – 120 km. They are divided into Utkal plains, Northern Circars and Coromandel coast spread across the states of West Bengal, Odisha, Andhra Pradesh and Tamil Nadu. Eastern Ghats have very gentle slopes with elevation of around 200-300m, due to this the alluvial soil carried by the east flowing rivers is deposited in these plains and form delta. Some of the major deltas formed by rivers like the Mahanadi, the Godavari, the Krishna, and the Cauvery.

Characteristics of Eastern Coastal Plains:

• These are example of Emergent plains, where land emerges due to the rise of tectonic plates or the receding of the sea.
• On the Eastern coast there are very few natural harbors. This is due to the fact that the continental shelf runs up to 500 km into the Bay of Bengal. 
• Large valleys and deltas have been carved out by the major rivers that run through this area. 
• Eastern Coastal Plains receive rainfall ranges from 1,000 mm to 3,000 mm.
• These plains are abundant in the sediments that contain oil reserves. The eastern offshore holds nearly 41% of India’s crude oil reserves.
• In the eastern coastal plains, agriculture is the most common occupation. Rice, legumes, sugarcane, cotton, wheat, gram, and oilseeds are key crops here.

Eastern Coastal Plains are divided into Three Parts:

A. Utkal Coast Plains:

Utkal coast plain marks the area between river Subarnarekha plains and Rushikulya River. This plain is bordered on the north by the Lower Ganga plain, on the east by the Bay of Bengal, on the south by the Andhra plains, and on the west by the Eastern Ghats. It covers an area of approximately 41,400 sq. km. Mahanadi, Brahmani, and Baitarani rivers form the major deltas in this region. Chilika lake is the largest lake in India located in this region. 

B. Northern Circars:

The Northern Circars got their name from the phrase “Northern Sarkars” which was used to describe British authority along the eastern coastline of the Madras Presidency. This plain covers roughly an area of 30,000 sq. km and lies between the Rushikulya river and the Krishna river. The Mahanadi, Godavari, and Krishna rivers form the important deltas in this plain. In recent years, the delta formed by these rivers has expanded 35 km toward the sea. The current site of the Kolleru Lake has demonstrated this, which was formerly a lagoon on the shore but now lies well inland.

Coromandel Coastal Plains:

The Portuguese derived the name Coromandel from the Tamil term ‘Cholamandalam’ which means ‘Realm of the Cholas’. This plain lies between the Krishna river in the north to Kanyakumari in the south, where it combines with the Western Coastal Plains. It spread over an area of 22800 sq. km. The Cauvery River creates important deltas in this region (Kaveri). The Kaveri, Penner, Palar, and other major rivers run through this coastal area.

Difference between Western Coastal Plains and Eastern Coastal Plains:

1. Western Coastal Plains are submerged plain while Eastern Plains are emergent plains.
2. Western coastal plains are very narrow with average width of 50km while Eastern coastal plains are wider with average width of 100-120km.
3. On western coastal plains rivers form estuaries while on Eastern plains rivers form large valleys and deltas.
4. Western Plains have many natural harbor while on Eastern coast there are very few natural harbors because of long continental shelf.
5. Western plains are mostly infertile except Malabar coast while Eastern plains are very fertile because of alluvial deposits.
6. Western coastal plains are steep and intersected by mountain ridges while Eastern coastal plains have very gentle slopes with elevation of around 200-300m.
7. Rivers flowing in Western plains drain their water into  Arabian sea while rivers flowing in Eastern plains drain into Bay of Bengal.