大象传媒

What is a river?

The River Thames
Image caption,
The River Thames

A river is a moving body of water that drains the land.

It flows from its source on high ground, across land, and then into another body of water. This could be a lake, the sea, an ocean or even another river.

Aerial photograph of a floodplain of the River Pripyat.
Image caption,
A floodplain of the River Pripyat.

A river flows along a channel with banks on both sides and a bed at the bottom.

If there is lots of rainfall, or snow or ice melting, rivers sometimes rise over the top of their banks and begin to flow onto the floodplains at either side.

Aerial photograph of a floodplain of the River Pripyat.
Image caption,
A floodplain of the River Pripyat.
Back to top

How are rivers formed?

A diagram of a meandering river in between two banks. Arrows show the water flowing around two rocks in the river.
Image caption,
Rivers meander where there is the least resistance. In this diagram, the river is moving around the rocks.

Rivers usually begin in upland areas, when rain falls on high ground and begins to flow downhill. They always flow downhill because of gravity.

They then flow and bend (meander) as they cross the land or go around objects such as hills or large rocks. They flow until they reach another body of water.

View over the Grand Canyon, USA.
Image caption,
The Grand Canyon

As rivers flow, they erode (or wear away) the land.

Over a long period of time rivers create valleys, or gorges and canyons if the river is strong enough to erode rock. They take the sediment (bits of soil and rock) and carry it along with them.

Small rivers are usually known as streams, brooks or creeks. If they flow from underground they are called springs.

View over the Grand Canyon, USA.
Image caption,
The Grand Canyon
Back to top

Watch: Rivers

Back to top

Why are rivers important?

Elephants in the River Chobe in Africa
Image caption,
Elephants in the River Chobe in Africa.

Rivers provide:

  • habitats for wildlife
  • freshwater for settlements, agriculture, and other industries
  • resources for leisure and tourism
  • navigation for exploration, trade and commerce
  • a means to transport nutrients and sediment
  • changing levels of energy that shape the landscape
  • energy for hydro-electric power
Elephants in the River Chobe in Africa
Image caption,
Elephants in the River Chobe in Africa.

Rivers and the water cycle

  • Rivers are an important part of the water cycle and responsible for transferring water to oceans.
  • Human activity is a main cause of pollution in rivers and oceans, and of some increased flooding events.
  • Flooding and drought can have catastrophic impacts on wildlife and people.
  • Careful environmental management can reduce flooding and pollution.
Back to top

River pollution

Kingfisher on a branch in a river.

Environmental charities say that rivers in the UK are being polluted by farm waste, abandoned mines and household sewage (things people flush down the toilet).

Animals such as kingfishers, dragonflies and otters rely on clean water to survive, so river pollution is a threat to wildlife.

People visit lakes and rivers to see and enjoy the wildlife living there. There are economic benefits as well as environmental ones for having healthy rivers.

Kingfisher on a branch in a river.
Back to top

River management

The Thames Barrier is an important defence against flooding for the capital city of London.

The impact of climate change means tidal flood risk will increase over time, unless this risk is carefully managed.

The Thames Barrier
Image caption,
The Thames Barrier
Back to top

Watch: Rivers in the UK

Learn more about the features and risks of rivers in this video from 大象传媒 Teach.

Back to top

Activity: Quiz 鈥 Rivers

Back to top

Bitesize Primary games. game

Play fun and educational primary games in science, maths, English, history, geography, art, computing and modern languages.

Bitesize Primary games
Back to top

More on The natural world

Find out more by working through a topic