The coastal plains spread as a fringe along the Arabian Sea and the Bay of Bengal. These plains owe their origin to the marine action and; alluvial deposition in the form of sediment. It is divided into two parts- the Western Coast and the Eastern Coast.
(a) Western Coast .
This coast starts from Gujarat and turns towards south and reaches the southern end of Kerala.
It is widest in Gujarat but becomes very narrow in the rest of the extension and its width varies from 10-25 km. This coast has a variety of relief features. The coast is divided as under:
(i) Gujarat Coastal Plain.
It stretches in Kachchh and in western Maharashtra. Its slope is western and south-western. The rivers like the Mabt, Sabarmati, Narmada, Tapti, etc. flow through this coastal plain.
(ii) The Konkan Plain.
It is 500 km long. It extends from Daman to Goa. It is almost plain and is 50-80 km broad.
(iii) The Karnataka Plain.
It extends from Goa to Mangalore. It is narrower in the north but becomes broader in the south with average width 8-24 km.
The rivers usually make estuaries. The Goa coast is famous for sea beaches and scenic beauty and attracts tourists from all over the world.
(iv) The Kerala Plain.
This plain extends from Mangalore to Kanya Kumari, a length of 500 km. It is a broader plain and is studded with beautiful lagoons and backwaters, which attract numerous tourists all the year round. It is known as Malabar Coast.
(b) Eastern Coast.
It extends from the river Subarnarekha in the north to Kanya Kumari in the south, a distance of nearly 1100 km. The average width of this coastal plain is 120 km. The rivers flowing into the Bay of Bengal have caused extensive sized deltas.
The north part of the coast is known as Northern Circars, whereas the southern one, the Coromandal Coast. East coastal plain is divided into:
(i) The Orissa Plain.
Also known as Utkal plain 400 km in length. It is a fertile delta of the Mahanadi River. South of it lies the Chilka lake (lagoon).
Besides, the Mahanadi river, there flow the Bhargavi, the Rishikulya, the Daya rivers. It is an agricultural area of the state.
(ii) Andhra Plain.
It extends from Bchramporc to Lake Pullicat. It includes fertile deltas of the Krishna and the Godavri rivers.
Lake Kolleru lies in between these deltas. It is an agricultural area of the state.
(iii) Tamil Nadu Plain.
It extends from Pullicat Lake to Kanya Kumari, a distance of 675 km. Average width is 100 km. The fertile Kaveri delta forms the agricultural belt of the state.