What are plains?

The meaning of plains

Plains are landforms with an extensive flat or gently undulating (rolling) surface. They do not have any large hills or deep valleys, and they are generally not more than 300 metres above sea level. Sea level is the average level of the surface of the oceans, also called mean sea level; heights of land are measured from it.

How rivers make floodplains

Floodplains are one type of plains, formed by rivers that start in mountain ranges. On their way, the rivers collect particles of rock, sand and silt, called sediments. They carry these sediments all the way to the plains and deposit them there, especially when they flood. The sediments make the soil very fertile, so these plains are ideal for growing crops of all kinds, and farming is the main occupation. Plains also support a variety of plants and animals.

Great river plains of the world include those of the Ganga and Brahmaputra and the Indus in South Asia, the Yangtze in China, the Nile in Africa, and the Mississippi and the Amazon in the Americas.

Life in the plains

Thousands of years ago, the first civilisations developed around rivers in fertile plains. Today too, a large part of the world’s population lives in plains.

About 40 crore people, more than one-fourth of India’s population, live in the Ganga plain, often called the Gangetic plain. As in many other plains:

• People work in farming and river fishing.
• Food crops such as rice, wheat, maize, barley and millets are grown.
• Fibre crops such as cotton, jute and hemp are grown too.

Irrigation and its cost

Traditional farming here was mostly rainfed, watered by rain. In recent decades, farming has turned to irrigation, with water brought by networks of canals or pumped from groundwater. Irrigation has increased production, but it has also caused the depletion of groundwater, a challenge for the future of farming in the region. High population and pollution are other problems of the Ganga plain.

Rivers, travel and culture

Because plains have a gentle slope, river navigation is easy and supports many economic activities. In earlier days, people used rivers a lot to travel from place to place; even today, on some stretches of the Ganga, people prefer boats to move around.

Rivers also carry great cultural value. Many communities consider a river’s source and its confluence, the meeting point of two or more rivers, to be sacred. In India, many festivals, ceremonies and rituals are held at such places: Prayagraj, where the Ganga and the Yamuna meet, is one well-known example.

Plains seen from space

A satellite photograph of north India shows the Ganga plain as a wide green expanse, the farmland of the plain. Above it, a white band marks the snow-covered Himalayas, and the brown land at the lower left is drier country with little green cover, towards the deserts and rocky uplands of the west.

Plains on the journey

On the chapter’s road trip, the land around Prayagraj is a plain: flat, fertile and green with fields, crossed by the Ganga and the Yamuna. It lies between the Chhota Nagpur Plateau to the south-east and the mountains around Almora to the north-west.

For the other landforms, read mountains and life in the mountains and what is a plateau. For the textbook’s questions, see the Chapter 3 NCERT solutions; for the whole chapter, see the Chapter 3 notes.