This presentation is describing about the water cycle. It explain about how water transfer in atmosphere, lithosphere, hydrosphere and biosphere.

1. Hydrological Cycle
D.G. Nishavi Kaushalya Ranasinghe
B.A. (Hons) Geography
Department of Geography & Environment Management
Sabaragamuwa University of Sri Lanka

2. What is Hydrological Cycle
■ Hydrologic cycle, cycle that involves the continuous circulation of water in the
Earth-atmosphere system.
■ Hydrological cycle also known as water cycle, H2O Cycle.
■ Many processes involved in the water cycle. As,
– Evaporation
– Transpiration
– Condensation
– precipitation
– Runoff

3. ■ The Hydrologic Cycle is one of the most important processes in the natural world.
■ The major component of the water cycle is “Sun”.
■ Water changes in to different states in this cycle. As,
• Liquid : Water
• Gas : Steam/ vapor
• Solid : Ice
■ The hydrologic cycle begins with the evaporation of water from the surface of the
ocean, rivers, lakes, tanks and etc.
■ Water also evaporation from the trees. It is known as transpiration.
■ Hydrological cycle describes the movement of water between the lithosphere,
biosphere, hydrosphere and atmosphere.
■ According to Wikipedia, “The water cycle, also known as the hydrological cycle or
the H2O cycle, describes the continuous movement of water on, above and below
the surface of the Earth.”

4. Diagram for Hydrological Cycle

5. • Starting point of the hydrological cycle is evaporation.
• Evaporated water vapor condenses and form clouds.
• Water vapor transport around the globe until it returns to the surface as
precipitation.
• After saturate the water vapor water reaches the ground as the precipitation.
• Once the water reaches the ground, one of two processes may occur;
1) some of the water may evaporate back into the atmosphere
2) the water may penetrate the surface and become groundwater.

6. • Groundwater either seeps its way to into the oceans, rivers, and streams, or is
released back into the atmosphere through transpiration.
• The balance of water that remains on the earth's surface is runoff, which
empties into lakes, rivers and streams and is carried back to the oceans,
where the cycle begins again.

7. Processes of water cycle
1. Precipitation
• Condensed water vapor that falls to the Earth's surface .
• Most precipitation occurs as rain, but also includes snow, hail, fog drip,
graupel, and sleet.
Rain Sleet Hail Snow

8. 2. Evaporation
■ Evaporation is the major process in water cycle. It transfer of water
from the surface of the Earth to the atmosphere.
■ By evaporation water transfer from liquid to gas.
■ The main factors affecting evaporation are temperature, humidity,
wind speed, and solar radiation.

9. 3. Transpiration
• Transpiration is the evaporation of water
through pores, or stomata, in the leaves of
plants.
• Transpiration and the evaporation from all
water, soils, snow, ice, vegetation, and
other surfaces are lumped together and
called evapotranspiration, or total
evaporation.

10. 4. Condensation
• Condensation is the process by which water vapor in the air is
changed into liquid water.
• It is responsible for the formation of clouds.
• Condensation is the opposite of evaporation.

11. 5. Run off
■ Run off is the water flowing in the land and it making the way to end
from lake, ocean, rivers and etc.
■ Its may be flow on surface or subsurface.
– Surface runoff: it is the running water over the land and which
ultimately discharge water to the sea.
– Subsurface runoff: The water getting infiltrated into pervious soil
mass, making its way towards rivers and lakes can be termed as
subsurface runoff.

12. 6. Infiltration
■ This is the process of filtration of water to the inner layers of soil.
■ Infiltration in soils like sand, gravel and coarser material is more and
for finer soil particles like clay and silt, infiltration is less.
■ In a soil, if infiltration is less, then runoff is more, similarly more
infiltration gives less runoff.