India has a long coastline. Based on the location and active geomorphological processes, it can be broadly divided into two: (i) the western coastal plains; (ii) the eastern coastal plains. They are formed because of sediments brought down by rivers as well as Sea.
Western coastal plains
- Extends from Gujarat to Kanyakumari
- They are an example of submerged coastal plain.
- Some geographers believe river Tapi as its northern most boundary while others believe Rann of Kutch as its northern most boundary.
- It is a narrow belt and provides natural conditions for the development of ports and harbours like Kandla, Mazagaon, JLN port Navha Sheva, Marmagao, Mangalore, Cochin, etc.
Initially it was an island which was joined with the mainland because of the sedimentation by river Indus. Its Western part is saline, salty and marshy. It is also known as ‘White desert/Salt desert.’ Luni river disappears in its Northern part. Three islands namely Pachham, Khadir and Bela are found in its northern part. Harappan site Dholavira is found in Khadir island.
Mandav hills are in the middle of the Kathiawar Peninsula. It has a centrifugal drainage system as rivers like Bhogwa, Bhadra, Machhu originate from it. South of the Mandav is the Girnar and Gir hills. River Shetrunji originates from Gir hills and drains into Gulf of Khambat. Barda hills lie in the western part.
- It extends from Daman to Goa. The width ranges from 50-80 Km. Rivers like Ulhas, Vaitarna, Zuari, Mandovi etc. drain these plains.
- It is extension of the West coast from Kali to Netravati river (Karwar to South Mangalore)
- Extends between Mangalore and Kanyakumari. Lakes, Lagoons and Backwaters (Kayal) enriches this area. Vembanard, Ashtamudi etc. are present in this region.
Eastern coastal plains
- The extend from Subarnarekha river in the North to Kanyakumari in the South.
- These are wider than the West coast plain because of excessive sedimentation at the Deltas of Godavari, Krishna, Kaveri. Chilika lake (Odisha), Pulicat lake (border of Tamil Nadu Andhra and Tamil Nadu) are the lagoon lakes and Kolleru lake (Andhra Pradesh) is a deltaic lake present in these plains
- From Subarnarekha to Mahanadi delta along Odisha coast.
- Extends from Chilika to Pulicat lake. K-G delta forms a major part of this.
Tamil Nadu plains:
Spreads from Pulicat to Kanyakumari. It has Kaveri delta in it.