Download The Water Cycle

The Water
Cycle
Arguably the most important natural
phenomenon on Earth, the water cycle, also
known as the hydrologic cycle, describes the
constant movement and endless recycling of
water between the atmosphere, land surface,
and under the ground. The hydrologic cycle
supplies the force needed for most natural
processes, thus supporting life itself.
The Water Molecule

H20 consists of one
atom of oxygen bound
to two atoms of
hydrogen. The water
molecule has a positive
charge on the side of
hydrogen atoms and a
negative charge on the
other side. Water
molecules tend to attract
each other because the
positive ends attract to
the negative ends.
 Water
is a
“universal
solvent: and
wherever it
goes
throughout the
water cycle, it
takes up
valuable
chemicals,
minerals and
nutrients.
Condensation
The change from a gas to a
liquid. In the water cycle,
the change from water
vapor to water.
Condensation
& Convection
 Warm
air rises
 Air cools and
can no longer
hold vapor
 Process known
as
CONVECTION
Condensation & Cloud
Formation
 Cooling
of
water vapor
forms CLOUDS
 Other ways
clouds are
formed
 Convergence
 Lifting of air
by fronts
Precipitation
Snow
 Snow
is a type
of precipitation
like rain but at
cooler
temperatures
 Usually reaches
the ground and
stays
 Eventually melts
and becomes
runoff in streams
Rain
 Type
of
precipitation
during warmer
weather
 Occurs when
clouds become
too full
 Falls to earth in
the form of
water and runs
off to streams &
rivers
Freshwater Storage
 Water
may be
stored
temporarily in
the ground,
oceans, lakes,
rivers, and ion
ice caps and
glaciers.
 The
world’s two
main reservoirs
of fresh water
are the great
polar ice caps,
and the ground.
 If all of the ice
in the ice caps
and other
glaciers melted,
it would raise
the sea level by
about 260 ft.
 In
temperate
climates, water
is found in
depression
storage or
surface water
puddles,
ditches, and
anywhere else
that runoff
water can
gather. This is a
temporary form
of storage
Freshwater Flow
A
hydrologist is
particularly
interested in
stream flow -the 31% of
precipitation
which runs off
into rivers,
streams and
lakes.
 About
3% of this
water will seep
underground
 About 31% will
run off into
rivers, streams
and lakes
 About 66% of the
water returns to
the atmosphere
through
evaporation and
transpiration
Surface Runoff
 When
precipitation
rate exceeds
infiltration rate,
or when soil is
saturated,
water begins to
move down
slope on ground
surface.
Surface Runoff

surface runoff
gradually flows
into gullies,
streams, lakes, or
rivers. Water in
streams and
rivers flows to the
ocean, seeps into
the ground, or
evaporates back
into the
atmosphere.
Water Storage in Oceans
Snowmelt Runoff to Streams
 Precipitation
falls in the form
of rain and
snow
 When the snow
melts it runs
into streams
which eventually
dump into the
ocean
Infiltration
-Rain water soaks
into ground through
soil and underlying
rock layer.
-Water cleaned
as impurities
filtered

-Some water
remains
underground as
groundwater.
-Some water returns
to surface at springs
or low spots
downhill.
Groundwater
Storage
- water seeps downward
underground into soil and rock
crevices
-then stored
underground in rock
crevices and in the
pores of geologic
materials that make
up the Earth's crust
-Water storage under the ground largely
depends on the geologic features related
to the types of soil and the types of rocks
present at the storage locations.
-underground
storage occurs in
the soil, in aquifers,
and in the crevices
of rock formations
Transpiration
The process of
evaporation
from plants.
Basically,
plants
sweating.
Transpiration Cont.
Environmental
factors that
affect
transpiration:
 Light
 Temperature
 Humidity
 Wind
 Soil water