Most of Earth’s water is in

its oceans and seas (97%)

Only 3% of Earth’s water is fresh water.

Most fresh water is frozen in glaciers and in

the North and South Poles

I.) Most fresh water on

Earth is frozen

A) Two –thirds of the fresh

water on Earth is in the form

of ice, mostly in huge ice

sheets that cover land near

the poles.

B.) These are continental glaciers.

Valley glaciers build up in

mountainous areas and flow slowly

down between mountains.

C.) Sometimes a chunk of a

glacier breaks off to form

an iceberg that floats in the

ocean.

D.) Only about 1/8

of the total

volume and

weight of an

iceberg floats

above the water

Underground water can be brought to the surface.

A) People collect groundwater from springs and wells.

B) A spring is a place where the surface of the land

dips below the water table and water bubbles up from

the ground.

C) A geyser is a special kind of hot spring that shoots

water into the air.

An estuary is the area where a river empties into and ocean.

1. The water in an estuary is a mixture of fresh and salt water.

||> important source of fresh

water.

||> Starts life as a melting

Glaciers

Three stages of Rivers

** Youth Age

** Maturity Age

** Old Age

• Youthful Stage

– Starts at its source and includes the steepest parts

of its course.

– Contains only trickle of water.

– The beds of streams are usually littered with

loose rocks and boulders.

– Usually found at higher elevation

– The channel is deeper than it is wide and V-

shaped due to down cutting rather than lateral

erosion

Scientist discovered that stream flowing

** at 0.3 miles (0.5km) per hour carries FINE

SAND along

** at 6 mikes (10km) per hour push SMALL

STONE down streams

** at 20 miles (32km) per hour move

BOULDERS

• Mature Rivers

– Flows down in a gentler slope but carries much more

water than in the youthful stage.

– The water is usually darker than the clear water of the

youthful.

– Tend to make their valleys broader rather than deeper .

This was called lateral erosion.

• WHY ?

– This is because attrition has crushed pieces of rock

and sand into very fine particles called silt which is

carried in the moving water.

• ATTRITION

– Process that gradually ground down into smaller particle.

• Old Age– The final stage of river before it empties into the sea.

– Carrying more water than either YOUTHFUL or Mature stages, but the gradient is much less.

– Across nearly flat land.

– Follow a winding path

– Swollen by heavy rain or by melted snow and ice

– May overflow their banks

– The water is usually dark and muddy.

– The channel is a U-shape

• Why ?– Because it is carrying a large amount of silt.

• What happen to the fine silt if the river flood?

– The flood plain spread over.

– This increases the quality of soil, making it better for growing crops

• Flood plain– Flat land on either side of the river

• Rejuvenated Stage

– A course of flowing water

with a gradient that is raised

by the Earth’s movement.