What do rivers provide?

Most settlements were built along major rivers. Rivers provide us with food, energy, recreation, transportation routes, and of course water for irrigation and for drinking.

Where does a river start from?

River Severn | River Thames

Every river has a 'source', a place where the river begins its journey.

Where is the source of a river?

The source of a river is usually found in high places such as hills or mountains. A river can have more than one source.

Different types of sources

Springs

Some rivers begin where a natural spring releases water from underground.

Lydwell spring

Lydwell Spring

The source of the River Thames is a spring.

Rainfall and melting snow

Some rivers begin in mountains or hills, where rain water or snowmelt collects and forms small channels, . At first, the channels are small and are called rills. As more water enters the channels they grow forming gullies (larger channels). The streams in the gullies eventually become big enough to form a river.

Lakes

The source of some rivers is a lake. The source of the River Nile is Lake Victoria, in Burundi.

Bogs

In some places, rain water can't sink into the ground as the ground is too wet already. The water forms a bog. The water flows out of the bog to form lakes and streams.

Why are rivers important?

River Severn | River Thames

Water

Rivers carry water and nutrients to areas all around the earth. They play a very important part in the water cycle, acting as drainage channels for surface water. Rivers drain nearly 75% of the earth's land surface.

Habitats

Rivers provide excellent habitat and food for many of the earth's organisms.

Many rare plants and trees grow by rivers. Ducks, voles, otters and beavers make their homes on the river banks. Reeds and other plants like bulrushes grow along the river banks.

Other animals use the river for food and drink. Birds such as kingfishers eat small fish from the river. In Africa, animals such as antelopes, lions and elephants go to rivers for water to drink. Other animals such as bears catch fish from rivers.

River deltas have many different species of wildlife. Insects, mammals and birds use the delta for their homes and for food.

Transport

Rivers provide travel routes for exploration, commerce and recreation.

boating

Farming

River valleys and plains provide fertile soils. Farmers in dry regions irrigate their cropland using water carried by irrigation ditches from nearby rivers.

Energy

Rivers are an important energy source. During the early industrial era, mills, shops, and factories were built near fast-flowing rivers where water could be used to power machines. Today steep rivers are still used to power hydroelectric plants and their water turbines.

The Stages of a River

River Severn | River Thames

Nearly all rivers have an upper, middle, and lower course.

Young River - the upper course

The beginning of a river, when it flows quickly with lots of energy, is called a young river. The river here is smaller and usually has a rapid, tumbling flow that cuts a narrow channel through rocky hills or mountains.

The fast flowing river can create waterfalls where it carves out layers of soft rock and leaves a cliff of hard rock standing.

Middle Aged River - the middle course

The middle of a river’s journey, when it gets wider and slows down, is called the middle age.

Middle course

Rivers often meander (follow a winding path) along their middle course.

The current of the river no longer has the force to carry stones or gravel. This material drops to the riverbed, where it forms bars of sand or gravel or builds islands.

Old River - the lower course

When the river reaches the end of its journey, it is called an old river. The end of the river is called the mouth.

Mouth of the River Thames

At the mouth, there is often a river delta, a large, silty area where the river splits into many different slow-flowing channels that have muddy banks.

The photograph below show the sediment (mud) that the Darent has brought with it on its journey to the River Thames.

Mouth of the River Darent

Features of a River

River Severn | River Thames

Our River Severn pages have many photos of the features of rivers. Follow ths link

Erosion

As a river flows, the force of its moving water washes away loose soil and pieces of rock. In this way the river cuts its own channel in the ground. The process of wearing away rocks is called erosion.

Click here to read more erosion

Gorge

A gorge is a steep-sided river valley which is very narrow and deep.

Click here to find out more about gorges

Meander

A meander is a bend in a river.

meander

Meanders normally occur in the middle and lower courses where the water is moving more slowly. The river carves out S-shaped bends.

Ox-bow Lakes

Find out more about ox-bow lakes on our River Severn pages

Mouth

At its mouth, the river flows into another body of water. The mouth may be where the river meets the sea, a lake or a larger waterway. Most rivers flow out into the sea, and this is where they end their journey.

Mouth of the River Severn

Mouth of the River Thames

Estuary

If a river has a wide mouth, this is called an estuary. An estuary has a mixture of salty and fresh water. The fresh water from the river extends out into the sea. Some of the salty water from the sea travels up the river mouth. This mixture of salt and fresh water is called brackish water.

The river carries a lot of sediment as it travels from its source to its mouth. When the fresh water from the river meets the salty water from the sea, the river drops its sediment. Most is then washed away by the sea, the river and the tides.

The Thames Barrier

Click here to find out more about the Thames Barrier

Dams

A dam is a barrier (wall) of earth, concrete or rock built across a river to restrict the flow of water.

Click here to find out about dams

Weirs

A weir is an artificial wall built across a river in order to make the river deeper.

Click here to find out more about weirs

A Lock

A lock and weir system is needed where the river bed is steep and the water flows too quickly.

Click here to learn more about locks

Flood Plain

The floodplain is the flat land of the river valley close to the river banks. The floodplain is usually found in the lower course of a river. It is a fertile area of land, used for agriculture and growing crops.

River Pollution

River Severn | River Thames

Many towns and factories are built near rivers so that they can use water from the river. But sometimes the water is not cleaned before it is put back into the river. This dirtying of water (also air and soil) is called pollution.

factory

Pollution can be in a variety of forms:

Rubbish like crisp packets, newspaper and bags.

Oil

Poisonous substances

Cans, bottles and other solid objects

Human waste / excrement

pollution from a factorytrolley

Causes of pollution

Agriculture

Farmers put fertilizers and pesticides on their crops so that their crops grow better. But these fertilizers and pesticides can be washed through the soil by rain, to end up in rivers. Fertilizers and pesticides are harmful because they cause algae to grow. The algae then destroy water plants.

pollution

Green algae

Factories

Factories use water from rivers to power machinery or to cool down machinery. Dirty water containing chemicals is put back in the river. Water used for cooling is warmer than the river itself, and this is also a form of pollution.

pollution

People

People are sometimes careless and throw rubbish such as bottles and crisp packets directly into rivers.

Effects of pollution

Pollution kills water plants and animals.

Polluted water also carries diseases. When animals drink the water, they may get diseases which can kill them. People can even get these diseases by eating the infected animal. This happens a lot in poor countries in Africa where people get untreated water directly from the river.

Rivers look unsightly when there is rubbish in them.

Polluted rivers smell bad.

Solutions

Efforts are being made to clean dirty rivers. Water companies like Southern Water are spending a lot of money to clean up dirty rivers. There are fines for companies and people who deliberately throw rubbish into the river.

Floods and Flooding

River Severn | River Thames

floodWhat is a flood?

A flood is water which covers land that is normally dry.

What causes Floods?

Floods are caused by extreme weather conditions.

Floods may be caused by:

rivers overflowing their banks after heavy rainfall

the sea flooding the land, as a result of heavy winds pushing the sea up against the coast

volcanic eruptions under the sea causing a huge wave, called a tsuanami.

When does flooding occur?

River flooding occurs when there is too much water for the ground to absorb, through infiltration, and the surface run-off overflows the normal river channel.

What is a flood plain?

A flood plain is the flat land on either side of a river that becomes flooded when a river spills from its channel.

Photos of a Flood

The photographs below show Tonbridge Sportsground at the start of the year 2003. The sportsground was submerged under more than three feet of water following 24 hours of downpours which left the area resembling a lake.

flood

We wont be flying our kites here today or playing football.

flood

Can you see the park bench and the bin beside it?

flood

Any one for a picnic?

The top of this picnic table is covered.

The flood water covered the whole recreation ground

including the children's play area.

flood

But it didn't stop the children having fun!

Tonbridge High Street Saved from Flooding

With the help of the Leigh Flood barrier and the re-inforced concrete wall built on the bank of the River Medway in Tonbridge, the town centre was protected from the rising water.

barrer

re-inforced concrete wall

Longest and Biggest Rivers

River Severn | River Thames

The River Nile is the longest river in the world. It measures 6,695 kilometres from its source in Burundi, along the White Nile, to its delta on the Mediterranean Sea. Officially, the shortesr river is the D River, Oregan, USA, which is just 37 metres long.

The biggest river in the world, measured by the amount of water that flows down it, is the Amazon. On average 120,000 cubic metres (about 20 swimming pools' worth) of water flows out of its mouth every second.

The longest river of Europe is the River Volga. It flows primarily in a southerly direction through Russia into the Caspian Sea. The second longest is the Danube, flows west to east before entering the Black Sea.

The longest Rivers of the World

The longest Rivers of the World

River Name LocationLength (miles approx)

Length (km approx)

Drainage Area(sq miles)

Flow at mouth (cubic m per second)

Nile Africa 4,160 6,695 1,170,000 1,584

AmazonSouth America

4,000 6,400 2,270,000 180,000

Yangtze Asia (China) 3,900 6,240 698,000 35,000

Mississippi USA 3,870 6,192 1,247,000 17,545

Ob Asia (Russia) 3,459 5,534 1,154,000 12,600

Yenisei/Angara

Asia (Russia) 3,440 5,504 996,000 19,600

Yellow River Asia (China) 3,440 5,504 290,000 1,365

Congo Africa (Zaire) 2,900 4,640 1,440,000 42,000

Amur Asia 2,800 4,480 730,000 12,500

Parana Uruguay 2,795 4,472 1,197,000 19,500

Lena Asia (Russia) 2,700 4,320 961,000 16,400

MackenzieNorth America

2,640 4,224 697,000 7,500

Niger Africa 2,600 4,160 850,000 5,700

Mekong Asia 2,500 4,000 750,000 15,900

Volga Europe 2,300 3,680 533,000 8,000

Murray-Darling

Australia 2,300 3,680 410,000 391

Rio-Grande USA 1,885 3,016 310,000 82

River Glossary

River Severn | River Thames

River Keywords and definitions. For photos with definition please visit our river keyword search.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Rounded pebbles and rocks

Abrasion

Abrasion is a form of erosion caused by rubbing of fine particles against an object. The effect is much the same as using sandpaper. Rivers carry sediment (fine rock particles) that abrade the banks and bed of the river channel.

Attrition

The wearing away of particles of rock as they bounce along the riverbed or knock against each other and wear away becoming more rounded.

Alluvium

The name for any material deposited by a river. (Silt is tiny material carried by running water)

Back to the top

B

River bank

Bank

The ground at the side of a river

Basin (Drainage basin)

The area of land that is drained by a river and its tributaries.

Bed (riverbed)

The riverbed is the ground at the bottom of the river - often made up of sand and stones.

Back to the top

C

River Cliff

Canal

An artificial or man-made river channel.

Channel

A groove in the land that a river flows along.

Cliff (river cliff)

A cliff is any steep slope that has been formed by natural processes. Cliffs reated by rivers are called river cliffs. They are on the outside of the curving section (meander) or a river and may be from a few metres to hundreds of metres high. Cliffs are formed when rivers cut swiftly into the land.

Current

The flow of the river.

Confluence

Where two rivers or streams meet.

Back to the top

D

Dam

Dam

A barrier built, usually across a watercourse, for holding back water or diverting the flow of water.

Delta

A fan-shaped area of sediment built up at the mouth of a river.

Deposition

A river lays down or drops the sediment or material that it is carrying such as sand, mud, and small stones or sticks. This often happens on the inside of meanders, because the water is flowing slowly.

Depth

How deep the water is.

Discharge

The amount of water flowing in a river per second.

Dock

A place for vessels to load and unload cargo or to be repaired.

Downstream

The direction that the river flows, towards the mouth of the river.

Drainage Basin

The area of land that is drained by a river and its tributaries. The boundary of a river basin is called the watershed.

Back to the top

E

Erosion

Erosion

The wearing away, in this case by water and rocks constantly rubbing

Estuary

A drowned river valley in a coastal lowland area. Occurs near or at the mouth of a river, where the tide meets the current and the fresh and salt waters mix.

Back to the top

F

Thames flood barrier

Fjord

A fjord is a deep, narrow flooded inlet of the sea that was formed during the last Ice Age.

Flood

Flooding happens when a river has too much water in its channel. The water breaks through the river banks and spreads over the surrounding land.

Flood barrier

A barrier forming a temporary dam that may be erected quickly or permanently alongside a river to protect a flood-prone area.

Floodplain

The flood plain is the flat land of the river valley close to the river banks. The floodplain is usually found in the lower course of a river. It is a fertile area of land, used for agriculture and growing crops.

Ford

A point where a road goes through a river.

Freshwater

Water that has no salt in it

Back to the top

G

Gorge

A gorge is a steep-sided river valley which is very narrow and deep. Most gorges have rocky sides. The river cuts this deep valley by erosion. Gorges are created over thousands of years.

H

Hydraulic Action

The force of the water wears away the river bank from underneath

I

Irrigation

The supply of water to farmland so that crops can grow in areas wherewater supplies are scarce or unreliable. In areas where there is not much rainfall, farmers irrigate the land, by diverting water from rivers to their fields, in channels, ditches or pipes.

L

Load

What the river carries along with it - mud, sand, rocks, wood

Back to the top

M

Meander

Meander

A bend in a river - usually in the middle or lower course. The meander continually changes shape as the fast flowing current of water erodes the outside bank of the meander bend and deposition occurs in the slack water of the inside of the bend.

Mouth

The end of the river. The mouth may be where the river meets the sea, a lake or a larger waterway. Most rivers flow out into the sea, and this is where they end their journey.

Moorings

The place where a ship or boat is docked (or tied up)

Mudflats

Mudflats are large area of mud that the tide washes over twice each day. They are rich in plant and animal life.

Back to the top

O

Oxbow lake

A small arc-shaped lake formed when a meander is sealed off by deposition. Oxbows are only found on river floodplains.

P

Pollution

Plain

A large area of nearly flat land which does not have any significant hills.

Plunge pool

A pool at the foot of a small water-fall in a river. The pool is deep because the water plunging into it has eroded the river bed.

Pollution

Materials that are not supposed to be in the river make it dirty.

Precipitation

A general term for all forms of water particles rain, snow, sleet, dew, hail etc.

Back to the top

R

Rapids

Rapids are fast-flowing stretches of water formed where the river surface breaks up into waves because rocks are near to the surface.

Ravine

Another name for a narrow gorge.

Reservoir

A reservoir is an artificial lake created by building a dam across a river.

River

A river is a naturally winding watercourse that drains surplus water from a drainage basin.

River channels

The trenches in which rivers flow for most of the year.

Runoff

Water that has from something. Usually rain water that has a roof into a gutter, or run - off sloping ground into a channel or pond.

Back to the top

S

Saline

Salty water - water from the sea is known as saltwater, or saline

Saltation

Particles bouncing down a river bed. This process causes attrition, and adds to the silt and sediment in the river

Sediment

The name given to material that has been carried by rivers or the sea and then deposited. Sediment may be called alluvium if it deposited on the bed or a river, it may be called a beach when deposited by waves.

Silt

Tiny pieces of sand or rocks. These are dropped by the water on the inside of a meander where the current is slow

Source

where the stream begins: usually where there is a spring, and quite high up

Spring

A place where water naturally seeps or gushes from the ground - often in marsh or bog areas

Spur

A ridge of land that extends partly across a valley.

Back to the top

T

Transportation

Transportation

A process where the river moves, or transports materials (it's load) from one place to another.

Tributary

A stream or river that feeds into a larger watercourse.

U

Upstream

Opposite to the currents flow - towards the source of the river

V

Valley

A valley is a long trough in the landscape that has been eroded by a river or a combination of river and glacier action.

V-shaped valleys are usually found in the mountains and hills. They are so called because they often have very steep sides.

W

Waterfall

Watershed

High ground that surrounds a drainage basin. The boundary of a river basin.

Waterfall

A place where the river course is interrupted by a tall step.

Water table

The water table is the natural level of water in a soil or rock. Below the water table the soil or rock is saturated.

Back to the top

http://primaryhomeworkhelp.co.uk/index.html

http://primaryhomeworkhelp.co.uk/rivers/source.html