Rivers and the Water Cycle

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Rivers and the Water Cycle
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The Water Cycle
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The Water Cycle
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Where do rivers start?

• Most rivers start in the mountains because lots
  of rain falls there.
• Some rivers start as springs.
• Others start in marshy areas.
• The place where a river starts is called its
  source.

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Where do rivers flow?

• The beginning of a river is usually called a
  stream.
• As streams flow downhill they meet with other
  streams to form larger rivers.
• Rivers flow downhill to the sea or a lake.
• This is because of a force called gravity.

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The upper course

• In its upper course the river flows quickly.
• You get waterfalls.
• It wears away the rock around it and cuts a
  V-shaped valley.
• This is called erosion.
• The force of the water can move stones, pebbles
  and soil
• .and sometimes even boulders.

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Reservoirs

• Dams are often built across rivers to make man
  made lakes called reservoirs.
• The water from reservoirs is pumped into peoples
  homes and to factories.

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The middle course

• As the river flows downhill the valley becomes
  wider.
• It flows more slowly.
• Settlements grow on the banks of a river.

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The lower course

• As the land becomes flatter the river meanders
  and often floods.
• Floodplains are usually very fertile, though they
  are often marshy.

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Floods

• Floods can cause tremendous damage to the land
  and buildings
• People often lose their lives in floods.

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Industry

• Factories are often located near rivers.
• This factory needs a lot of water for its cooling
  towers.

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The lower course

• As a river approached the sea, it is wide and
  flows through flat land.
• Ships can navigate quite far up wide rivers.
• The ships could carry passengers or cargo.

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The estuary

• You often get mudflats near the mouth of the
  river.
• Some plants grow well on the mudflats and they
  often attract wildlife.
• People often sail their boats in these estuaries.

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The mouth of the river

• At the river mouth there may be harbours and or
  docks.
• These may be for fishing boats, cargo boats or
  ferries. Anchoring in the river means the boats
  are safe from rough seas.