Important Definitions:

Plains

Plain is a broad area of relatively flat land. They cover more than one-third of world’s land area.

Grassland

Grassland is a region where grass is the main type vegetation. For example, the Indus Plain in Pakistan (including upper Indus Plain and lower Indus Plain) and the Great Plains that stretch across much of Central north America.

Steppes

In Asia and Eastern Europe, temperate grasslands are called steppes. Steppes usually do not receive enough rain for tallgrasses and trees to grow.

Tundra

In the Arctic, where the ground is frozen, plains are called Tundra.

IMPORTANT POINTS TO REMEMBER:

• River Nile is said to be “Gift for Egypt”, because it provides fertile soil which supports agriculture.
• Pakistan has a coast line of almost 1058km with Arabian Sea.
• River flows from higher elevation to а lower elevation, due to gravity.

Major Types of Plains:

Erosional Plain

These plains are formed in millions of years due to action of various agents like river, glacier and wind. For example, Lorraine Plain in France.

Depositional Plain

This type of plain is formed by deposition of sediments brought down by rivers, glaciers, and winds. For example, the Indus plain of subcontinent.

River Plain

This plain is formed when a river deposits its sediments on their flood plains or beds over a long period of time. For example, the Indus River Plain.

1. Alluvial Plains: When the river enters into the plain stage, the slope and speed of that river reduce which cause deposition of the alluvium brought by the river forming Alluvial Plain. For examples, Indo Gangetic Plain across India, Bangladesh and Pakistan, Po Valley in Italy, etc.
2. Flood Plain A flood plain refers to an area of flat land along river sides. Flood plains are usually subjected to flood when the adjacent water body overflows. These plains are often fertile and good for agriculture. For example, the Indus Plain.

Glacial Plain

Glacial plains are formed by the material accumulated by a glacier. For example, Outwash plain.

Lacustrine Plain

A Lacustrine Plain or Lake Plain is formed due to the past existence of a lake. For example, The Kashmir Valley.

Coastal Plain

A coastal plain is a piece of land that is lying low and Plain is adjacent to the sea coast. For example, Southeastern coastal plain of North America.

Wind Plain

Wind plain is a broad, flat area of desert covered with wind-swept sand with little or no vegetative cover.

Pedi Plain

When the high relief structures in deserts are reduced to low featureless plains by the activities of wind, they are called as Pedi plains.

Features Formed by River:

Flood Plain

Flood Plains are formed when river’s water comes out of its channel and spreads over vast stretches of land. During this process it deposits its sediments in the areas. In this way a smooth Plain comes into existence, which is called flood Plain.

Ox-bow Lakes

When a river enters into a plain area, it twists and turns forming large bends or meanders. Due to continuous erosion and deposition along the sides of the meander, the ends loop close, and after a while, cut off from the river and form Ox-bow lakes.

Meanders

A mature course is developed when water moves down the slope slowly under the force of gravity. The water does not move in a same direction for long distances. The irregularities of the ground, force the river to flow/swing in loops, forming meanders.

Natural Levees

Levees are formed by the repeated flooding of the river. When the river flooded, the coarsest material deposits, close to the river banks. This may continue to build up the levees over time.

Distributaries

When a river approaches the sea, its speed decreases and it breaks down into a number of streams known as distributaries. The shape of these distributaries is like symbol of delta, so it is called river delta.

River System

A river is made up of different small tributaries. Tributary is a fresh water channel feeds into a large river. This channel of tributaries and the main river is called river system. The area that a river system covers is called basin.

CRITICAL THINKING QUESTIONS:

Physical Features of Plains

1. Plains are vast stretches of flat land.
2. Plains are usually fertile regions.
3. They are usually thickly populated regions.
4. It is easy to build houses, roads, etc. in plains.
5. They are suitable for cultivation.

Investigate reasons why Arctic Plain is known as barren plain?

1. Extreme Cold Temperatures: Average winter temperatures can plummet to -34°C, with summers only reaching 3-12°C. These frigid conditions make it difficult for most plants to survive or grow beyond low-lying shrubs, mosses, and lichens.
2. Permafrost Layer: The ground remains permanently frozen (permafrost) below a shallow active layer, preventing deep root systems and trapping moisture near the surface while limiting nutrient availability.
3. Low Precipitation and Short Growing Season: Annual precipitation is minimal, around 357 mm (14 inches), much of it as snow, and the growing season lasts only 50-60 days. This results in poor soil nutrients and a landscape dominated by rocky, barren terrain rather than lush vegetation.
4. Lack of Trees and Limited Biodiversity: No trees can grow due to the combination of factors above, leading to a fragile ecosystem that’s shrinking with climate change.

Investigate the living conditions in a desert or the Arctic Tundra Plain.

• For Humans: Indigenous groups and nomadic herders live in tents, igloos, or modern settlements, relying on insulated clothing, hunting, fishing, and herding. Communities face isolation, limited access to resources, and risks from blizzards or melting permafrost due to climate change. Modern adaptations include heated homes and snowmobiles, but traditional knowledge is key for survival.
• For Wildlife: Animals like caribou, arctic foxes, lemmings, and polar bears thrive through migrations, burrowing for shelter from winds, and thick fur or fat layers. Plants are low-growing and perennial to withstand the short growing season and nutrient-poor soils. Many species remain year-round, finding refuge under snow or in microhabitats.

Difference Between Plains, Plateaus, Mountains And Valleys

The main difference between plain and plateau lies in their elevation. A plateau is a flat land that is raised significantly above the ground whereas plain is a flat yet low-lying area. Mountains have steep slopes with a pointy summing. They are the highest natural landscapes. A valley is a deep depression between mountain peaks, hills or plateaus that forms over millions of years usually due to fast flowing water.

Importance of the Upper Course of the River

• The main function of a river in its upper course is erosion.
• It erodes its bed and banks and carries large boulders of rocks with it.
• The landforms formed in the upper course of a river are V-shaped valley and waterfall.

Importance of the Middle Course of the River

• The middle course of a river has more potential and volume than in the upper course.
• The gradient is gentler and lateral (sideways) erosion has widened the channel.
• This happens in upper stage where river does inward erosion.
• Meanders are typical landforms found in this stage of the river.

Importance of the Lower Course of the River

• The volume of water in a river is highest in the lower course.
• This is due to the contribution of water from tributaries.
• The river channel is deep and wide and the land around the river is flat.
• Energy in the river is at its lowest due to load of sediments and deposition occur.

Why Delta is Found on the Lower Course of the River?

A delta is a marshland area that forms as river water falls into a larger body of water. Often, delta is looked like triangular in shape and sometimes it is even described as looking like a fan. River collects soil particles and rock debris called sediment. These sediments flow along the river until it is deposited at the river’s mouth. These sediments collected, low-lying plains are created, and a delta is formed.

Importance of Rivers in the Biodiversity

1. Rivers provide excellent habitat and food for many land organisms.
2. Many rare plants and trees grow by rivers.
3. Ducks, voles, otters and beavers make their homes on the river banks.
4. Many animals depend on river for food and water.
5. Birds such as kingfishers eat small fish from the river.
6. Insects, mammals and birds use the delta for their homes and for food.

Importance of Rivers in Economy

1. Rivers help to generate hydro-electricity.
2. They enhance fertility to the soil.
3. Rivers provide water for irrigation.
4.  Rivers are best sites of tourism.
5. They provide water for various domestic uses.
6. They provide livelihood to fishermen.