Geography · Ch 2 — Structure and Physiography
The Coastal Plains
The Coastal Plains
The photograph shows a calm, palm-lined waterway typical of Kerala’s backwaters. Tall coconut palms rise along both banks, their trunks leaning slightly over the water, while a group of people stands in the shallow water near the shore, working — likely fishing or tending nets. The scene is flat and quiet, with no hills or surf, which is exactly the look of a kayal: a brackish lagoon separated from the sea by sandbars, fed by rivers and tides alike.
What the image captures is the defining landform of the Malabar coast, the southernmost stretch of India’s western coastal plain. Unlike the rest of the west coast, which is narrow and rocky, the Malabar coast opens into these elongated, almost lake-like bodies of water. The palms and the working fisherfolk are not decoration — they point to how the kayals are lived in. The text tells you these backwaters are used for fishing, inland navigation, and tourism, and the photograph shows all three at once: the water itself is the highway, the palms shade the shore, and the people in the shallows are harvesting it.
Geomorphologically, the kayal is a product of submergence. The western coastal plain as a whole is a submerged coast — the land sank relative to the sea, drowning old river valleys and leaving the shoreline irregular and indented. In Kerala, that drowning created these shallow, sheltered lagoons. Because the coast is submerged, rivers here do not build deltas; they simply empty into the sea through these backwaters. The photograph quietly illustrates that: there is no broad, flat delta fan, just a narrow strip of water and land. …
India’s coastline is long, but it is not uniform. Depending on where the coast lies and the geomorphic processes that shaped it, the coastal plains split into two broad belts: the western coastal plains and the eastern coastal plains. The difference between them is not just location — it is a difference in how the land met the sea.
The Western Coastal Plains
The western coastal plains are a submerged coast. The land here has sunk relative to the sea, and the sea has invaded what was once land. The most striking evidence is the city of Dwaraka, which is believed to have been part of the Indian mainland along the west coast and now lies submerged under water.
Because of this submergence, the western coastal plain is a narrow belt. But the same submergence that narrowed the land created deep, sheltered inlets — natural conditions ideal for ports and harbours. Some of India’s most important natural ports lie along this coast: Kandla, Mazagaon, Jawaharlal Nehru Port at Navha Sheva, Marmagao, Mangalore and Cochin.
From north to south, the western coast runs from the Gujarat coast to the Kerala coast and is divided into four stretches:
| Stretch | State |
|---|---|
| Kachchh and Kathiawar coast | Gujarat |
| Konkan coast | Maharashtra |
| Goan coast | Goa |
| Malabar coast | Karnataka and Kerala |
The western coastal plains are narrow in the middle and become broader towards the north and south. The rivers that flow through this plain do not form deltas — they reach the sea without building the fan-shaped deposits typical of eastern rivers.
The Malabar coast has a special feature: Kayals, or backwaters. These are shallow lagoons running parallel to the coast, and they serve three purposes — fishing, inland navigation and tourism. The most famous event connected to them is the annual Nehru Trophy Vallamkali (boat race), held in Punnamada Kayal in Kerala.
The Eastern Coastal Plains
The eastern coastal plain is the opposite case. It is an emergent coast — land that has risen relative to the sea. As a result, it is broader than its western counterpart.
The rivers flowing eastward into the Bay of Bengal have built well-developed deltas here. These include the deltas of the Mahanadi, the Godavari, the Krishna and the Kaveri — four major river systems that have pushed the coastline outward with their sediment. …