Western coastal plain

Also called: West coast · Topic: Structure and Physiography of India: Himalayas, Plains, Peninsula, Coasts and Islands · NCERT: Class 7, Ch 1 "Geographical Diversity of India"; Class 11, Ch 2 "Structure and Physiography"

Meaning

The Western coastal plain (west coast) is a narrow strip of low, flat land between the Western Ghats and the Arabian Sea. It runs from Gujarat in the north to Kerala in the south. It is a submerged coast (a coast where the land has sunk, so the sea has flooded its low parts). It is narrowest in the middle (Konkan–Goa) and broader in the north (Gujarat) and south (Kerala).

It matters because its drowned shape gives India many deep natural harbours. It also explains why the west coast has estuaries and no deltas.

Explanation

How it formed: a sinking coast

• The land sank, so the sea moved in:
• The sea flooded river valleys and low ground.
• River mouths and valleys were "drowned".

• This left deep, sheltered inlets close to the shore.

• Proof of sinking: the ancient city of Dwaraka (Kathiawar peninsula, Gujarat) is believed to have been on the mainland. Today it is believed to lie under the Arabian Sea.

• Result: a coast full of:
• coves (small, curved bays)
• creeks (narrow inlets of the sea)
• estuaries (wide, funnel-shaped river mouths where river water mixes with sea water and the tide moves in and out)

Why there are no deltas

• A delta is fan-shaped land made of silt. It forms where a river drops its silt at the mouth faster than the sea can carry it away.
• Short, swift rivers:
• The rivers fall fast from the Western Ghats down a steep slope.

• They have no time to drop their silt on the plain.

• Sinking coast:

• The land went down, so river mouths were drowned.
• They became estuaries, not deltas.
• Examples: the Narmada and Tapi. Both flow west into the Gulf of Khambhat (Arabian Sea).

Why it has many natural harbours

• Drowned coast → deep water near the shore → good ports:
• Flooded valleys form deep, sheltered inlets.
• Big ships can come close to the land.
• So natural harbours grow here with little digging.

Parts, from north to south

Part	State(s)	Key features
Kachchh and Kathiawar coast	Gujarat	Broadest northern part; drowned Dwaraka; Kandla (Deendayal) port
Konkan coast	Maharashtra (Daman to Goa)	Narrow, rocky, cut by creeks; very heavy rain
Goan coast	Goa	Marmagao (Mormugao) port
Malabar coast	Kerala and coastal Karnataka	Broader southern end; kayals (backwaters), coconut, spices; very heavy rain

• Why it rains so much (south-west monsoon, June–September):
• Moist south-west winds hit the Western Ghats and are pushed up.
• Rising air cools, and its water vapour condenses.
• Heavy rain falls on the coast and on the side of the hills facing the wind (the windward side).

• The monsoon reaches the Malabar coast first.

• Kayal (backwater): a shallow lake near the sea, cut off by a sand bar (a long ridge of sand built by waves and currents).

• Waves pile sand into bars.
• The bars close off shallow bays and river mouths.
• Calm, shallow water forms behind them. These are the Kerala backwaters, used for fishing, boat transport (inland navigation) and tourism.

Where it occurs

• Gujarat: the Kachchh and Kathiawar coast. It has drowned Dwaraka and Kandla port, renamed Deendayal Port from 25 September 2017 [4]. The Narmada and Tapi estuaries open into the Gulf of Khambhat.
• Maharashtra: the Konkan coast (Daman to Goa). Ports: Mazagaon (Mumbai) and Jawaharlal Nehru Port (Nhava Sheva), near Mumbai.

• The Konkan Railway runs 741 km from Roha (near Mumbai) to Thokur (near Mangaluru), through Maharashtra, Goa and Karnataka. It has 84 km of tunnels and opened fully on 26 January 1998 [3].

• Goa: the Goan coast, with Marmagao (Mormugao) port.

• Karnataka: Mangaluru (New Mangalore) port, on the coastal Karnataka stretch of the Malabar coast.
• Kerala: the Malabar coast, with Kochi (Cochin) port and the Kerala backwaters.
• Vembanad is the largest kayal. It is part of the Vembanad-Kol Wetland, a Ramsar site since 19 August 2002, covering 151,250 ha and fed by 10 rivers [2].

• The Nehru Trophy Vallamkali (snake boat race) is held on Punnamada Kayal, part of Vembanad lake, near Alappuzha.

• Major Ports on the west coast (6 of India's 12): Deendayal (Kandla), Mumbai, Jawaharlal Nehru, Mormugao, New Mangalore and Cochin [5].

Don't confuse with

• Eastern coastal plain: an emergent coast (land rose), lying between the Eastern Ghats and the Bay of Bengal. It is broad, has big deltas and fewer good natural harbours. The west coast is submerged, narrow and has estuaries.
• Delta vs estuary: a delta is new land built of silt at a river mouth (Mahanadi, Godavari, Krishna, Kaveri). An estuary is a drowned, funnel-shaped mouth with no silt fan (Narmada, Tapi).
• Kayal vs lagoon (Chilika, Pulicat): both are shallow water cut off by a sand bar. But kayals are the Kerala (west coast) backwaters, with Vembanad the largest. Chilika (Odisha) and Pulicat (Andhra Pradesh–Tamil Nadu border) are large lagoons on the east coast.
• Malabar vs Coromandel: Malabar (Kerala, west) gets heavy rain from the south-west monsoon (June–September). Coromandel (Tamil Nadu, east) gets most of its rain in October–December from the north-east monsoon.

Prelims Hooks

• Order, north → south: Kachchh-Kathiawar → Konkan → Goan → Malabar.
• Submerged coast evidence: drowned Dwaraka (Gujarat). Trap: questions that call the west coast "emergent".
• Narmada and Tapi form estuaries, not deltas. Both flow into the Gulf of Khambhat.
• Konkan coast = Maharashtra, Daman to Goa. Malabar coast = Kerala and coastal Karnataka.
• Port–state pairs: Deendayal/Kandla (Gujarat, renamed 2017) [4], Mormugao (Goa), New Mangalore (Karnataka), Kochi (Kerala).
• Vembanad is the largest kayal. Vembanad-Kol became a Ramsar site in 2002 [2]. The Nehru Trophy boat race is held on Punnamada Kayal.

Mains Points

• Coast type shapes the economy (GS-I, GS-III):
• A sinking coast gives deep, sheltered inlets.
• These become natural harbours (Mumbai, JNPT, Mormugao, Kochi).

• The harbours support port-based industry and trade with West Asia and Europe.

• Hazards along the narrow west coast (GS-III Disaster Management):

• The very heavy south-west monsoon causes floods and landslides along the Ghats and the Konkan rail route.
• The rocky, creek-cut coast and steep Ghats made the Konkan Railway one of India's hardest rail projects [3].

• Hazard mapping and coastal protection (mangroves, shelterbelts) are key responses.

• Wetlands under pressure (GS-III Environment):

• Vembanad-Kol is a Ramsar site [2], but it faces silting, changing salt levels, land reclamation, aquaculture and tourism pressure.
• Managing it sustainably protects fisheries, waterbirds and local jobs.

Related concepts

• Coastal plains of India
• Konkan coast
• Malabar Coast
• Kerala backwaters
• Eastern coastal plain
• Coromandel Coast

Read more

• The Coastal Plains: a submerged west and an emergent east