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1. Catchment
The catchment is
defined as the area
drained by a stream or a
system of connecting
streams such that all the
surface runoff
originating in this area
leaves the area in a
concentrated flow
through a single outlet.

4. HYDROLOGIC CYCLE
 The hydrologic cycle is the system which describes the
distribution and movement of water between the earth
and its atmosphere.
 The model involves the continual circulation of water
between the oceans, the atmosphere, vegetation and
land.

6. The Water Cycle has 9 stages
• Evaporation
• Condensation
• Precipitation
• Interception
• Infiltration
• Percolation
• Transpiration
• Runoff
• Storage

7. Evaporation
changing of water
from liquid to gas
Evaporation
Solar energy powers the cycle.
Heat energy from the sun causes
evaporation from water surfaces
(rivers, lakes and oceans)

8. How does evaporation take place?

9. Condensation
Changing of Water
from Gas to Liquid

10. Precipitation
Water particles fall
from the sky
Precipitation occurs,
either as rain or snow
depending on altitude

11. Interception
Interruption of the movement of water

12. Infiltration
Water in and through soil
Infiltration is defined as the downward entry of water into
the soil or rock surface

13. Percolation
Ground water flow
percolation is the flow of water through soil and porous or
fractured rock.

14. Transpiration
Water in plants to water vapor

15. Runoff
• Streams
• Rivers
• Lakes
• Oceans
FLOW OF WATER TO LARGE BODIES OF WATER
Johnson, Amanda “Water Cycle 7” September 29, 2010 via Paint, Creative Commons Attribution

16. Storage
Atmosphere, on Earth surface, in ground

18. Front
The border between air masses of different
temperature, pressure and moisture content is
called a front.
There are two types of front
• cold front
• warm front

19. When 2 or more different air masses meet,
the place where they bump is called…
Front
Warm air mass Cold air mass
A storm, usually with precipitation, occurs at this front.

20. TYPES OF PRECIPITATION.
Lifting mechanism gives the three main types of
Precipitation.
 Cyclonic Precipitation (Frontal /non Frontal)
 Convective Precipitation
 Orographic Precipitation

21. Precipitation
Precipitation
It is defined as the return of atmospheric moisture to
the ground in the form of solids or liquids.. Solid form-
snows, sleet, snow pellets, hail stones. Liquid form-
drizzle, rainfall.
1. Cyclonic Precipitation- This is the precipitation
associated with cyclones or moving masses of air and
involves the presence of low pressures.
This is further sub divided into 2 categories-
a. Non Frontal cyclonic precipitation-
b. Frontal cyclonic precipitation-

22. PRECIPITATION
a. Non Frontal cyclonic precipitation-
 In this, a low pressure area develops.
(Low-pressure area is a region where the atmospheric
pressure is lower than that of surrounding locations.)
 The air from surroundings converges laterally towards the
low pressure area. This results in lifting of air and hence
cooling. It may result in precipitation.

23. PRECIPITATION
 Frontal cyclonic precipitation-
 FRONT is a barrier region between two air masses having
different temperature, densities, moisture, content etc.
 If a warm and moist air mass moves upwards over a mass of
cold and heavier air mass, the warm air gets lifted, cooled
and may result in precipitation. Such a precipitation is
known as warm front precipitation.
 The precipitation may extend for 500km ahead of the front i.e.
the colder air region.
 If a moving mass of cold air forces a warm air mass upwards,
we can expect a cold Front precipitation.
 The precipitation may extend up to 200kms ahead of the Front
surface in the warm air.

24. Cyclonic Precipitation
(Frontal/Non frontal)

25. Convective Precipitation
Convectional precipitation
results from the heating of the
earth's surface that causes air
to rise rapidly. As the air rises,
it cools and moisture condenses
into clouds and precipitation

26. Orographic Precipitation
It results when warm moist air of the
ocean is forced to rise by large
mountains. As the air rises it cools,
moisture in the air condenses and clouds
and precipitation result on the windward
side of the mountain while the leeward
side receives very little.
This is common in British Columbia.

27. Forms of Precipitation
Drizzle
 This is a form of precipitation consisting of water droplets
of diameter less than 0.05 cm with intensity less than
0.01cm/ hour.
Rainfall
 This is a form of precipitation of water drops larger than
0.05cm diameter up to 0.5 cm diameter.
 Water drops of size greater than 0.5 cm diameter tend to
break up as they fall through the atmosphere.
 Intensity varies from 0.25 cm/ hour to 0.75cm/ hour.

28. Forms of Precipitation
Glaze
 This is the ice coating formed when a drizzle or rainfall
comes in contact with very old objects on the ground
Sleet
 This occurs when rain drops fall through air which is below
00c.
 The grains are transparent, round with diameter between 0.1
cm to 0.4 cm.
Snow
 This is precipitation in the form of ice crystals, usually a no.
of ice crystals combining to form snowflakes.

29. Forms of Precipitation
Hails
 These are balls or irregular lumps of ice of over 0.5cm
diameter formed by repeated freezing and melting.
 These are formed by upward and downward movement
of air masses in turbulent air currents.

30. Hails