Transcript Hydrologic Cycle

Biogeochemical
Cycles
describe the flow of
essential elements
from the environment
through living
organisms and back
into the environment.
Hydrologic Cycle
How come we never
run out of water?
ECOWLEC
Juvena May Alegre
After four and a half million years you’d
think the water would be all used up!
It’s
not, though, because of one special
hydrologic cycle,
more commonly called “the Water
Cycle.”
process: the
ECOWLEC
Juvena May Alegre
The Hydrological Cycle
(also known as the water cycle) is the
journey, water takes as it circulates
from air, the land , subsurface waters, and
organism to the sky, and back again.
ECOWLEC
Juvena May Alegre
Water is
Ubiquitous!
Biosphere- Water Cycle
Hydrosphere
• Liquid waters of
earth.
Atmosphere
• Layer of gases
surrounding earth.
1. Oceans
1. Clouds
2. Lakes
3. Streams
4. Glaciers
2. Vapor
Earth is a closed system:
The water available on
Earth , today, is the same
water that has always
been available and the
only water that ever will
be available!
How much Water do We Have?
Fresh Water
≤ 1 % of Earth’s water is available for the
following:
• Support organisms such as: plants,
bacteria, humans
• Support industry, agriculture
• Provide a source of recreation
• Hydropower plants- energy
• Transportation
• Habitats
• Waste processing
Earth’s Water Budget
How the water is
divided among:
• Ocean
• Land
• Atmosphere
Proportions of water
remains relatively
stable on Earth. Only
the distribution
differs (tropical vs
desert).
Baby water cycle concept
The elementary water cycle:
Better…
EVEN BETTER, but still lacks time
and amount information!(like 90%
of clouds are from ocean
evaporation)
Water Cycle
The actual path
any given water
molecule follows
in a complete
water cycle can
be varied and
complex and may
not follow the
exact path shown
by a diagram.
Water is Always on the Move
From Atmosphere
to Surface
1. Condensation
2. Precipitation
From Surface to
Atmosphere
1. Evaporation
2. Transpiration
3. Sublimation
Sublimation: from solid
to gas without
melting.
Snow or ice 
vapor
What happens to 100 drops of rain
fall?
2 Goes into
“ground water”
2 make it into our faucets
67 drops go back into
the sky
Within a week
29 of them go into creeks and rivers
But… how do those 67 drops make
it back? IN TEXAS..
2 Goes into
“ground water”
2 make it into our faucets
67 drops go back into
the sky
Within a week
29 of them go into creeks and rivers
But… how do those 67 drops make
it back? IN TEXAS..
2 Goes into
“ground water”
2 make it into our faucets
33 drops evaporate
directly
34 drops make it via
TRANSPRIATION
29 of them go into creeks and rivers
Evaporation
From liquid to vapor
• 80% of all water
entering the
atmosphere originates
from the ocean.
• Transfers energy from
the earth’s surface to
the air above.
Latent energy: hidden
heat energy
Latere- (Lat.) to lie hidden
Transpiration:
The process of
transferring water
from the roots up
to the leaves of
the plant to
facilitate nutrient
transfer. The
water is
evaporated at the
leaves.
Water Vapor
• Odorless, colorless gas that
mixes with other gases in the
atmosphere like N2 and O2. These
gases make up 99% of the
atmosphere.
• The amount of water vapor varies
from less than 1% to 4% in the
atmosphere.
Condensation
• Water vapor cools in the upper
atmosphere to form drops or ice.
• Releases latent heat warming the
air.
• The released heat may trigger
storms.
Clouds
A mass of liquid droplets or
frozen crystals.
1. Earth’s water
transportation system.
in conjunction with wind
2. Determine how much of
earth energy is absorbed.
block solar rays
3. Alters temperature of
air on earth’s surface
traps heat on the surface
The process of evaporation and
condensation purifies water
naturally.
Evaporation: only the water molecules
leave the surface; the dissolved salts and
other solids remain behind in solution.
Condensation: when the water vapor
condenses again it is pure. It may
become contaminated as it falls through
the atmosphere: sulfates and nitric oxides
( NOx) cause acid precipitation.
Precipitation
Water droplets coalesce to form
precipitation.
Gravity pulls it to the earths
surface.
• Hail
• Rain
• Sleet
• Snow
Precipitation
Interception: falls on leaves or stems
of plants.
Percolation: moves down
into the soil and ground
water.
Runoff: does not infiltrate soil but
travels across the surface of land.
• Subsurface Flow
– movement of water within the
earth, or within aquifers.
ECOWLEC
Juvena May Alegre
Ground Water
Together ground water and soil
water make up .5% of freshwater.
Ground Water Zones
1. Unsaturated- soil and water
2. Saturated- ground water
Vadose: soil moisture
Water table: divides the
2 zones.
Zone of Saturation
Aquifer- body of earth
material that has the
ability to hold and
transport water.
•
Unconfined- “open”
connected to the surface
above.
•
Confined- “closed”
sandwiched between
dense impermeable layer
of earth.
Groundwater Movement
• Replenished by
percolation from
zone of aeration
downward to
zone of
saturation.
Recharge zone- where confined
aquifer is exposed at the surface.
Groundwater flow
ground
water flows to
a stream
channel, lakes,
and wetlands
Seepage:
Hydraulic conductivity- the
measure of the ability of a
material to transport water.
Lets talk TIME for a second
How long does it STAY in each place.
This is called “residence time”
• Some places you can guess have
LONG residence times
– Oceans, lakes, glaciers, groundwater
• Some places you can then guess
have SHORT residence times
– Clouds, rivers, soils, animals and plants.
Lets talk SPECIFIC times
Reservoir
Average residence time of a
water molecule
Antarctica
Oceans
20,000 years
3,200 years
Glaciers
Snow
Soil moisture
20 to 100 years
2 to 6 months
1 months
Groundwater
Lakes
Rivers
100 – 10,000 years
10 to 100 years
1 to 6 months
Atmosphere
9 days
A single cloud 40 minutes
Lets talk Water USES
Farm use
City use
• Drinking
• Um.. duh
water
• Sanitation
• Lawn
• Car
washing
Industry use
• making
energy.
• Cooling plants
• Used in the
manufacturing
process
Human Connection
United States
Family
Effects of Human Activities
on Water Cycle
• We alter the water cycle by:
– Withdrawing large amounts of freshwater.
– Clearing vegetation and eroding soils.
– Polluting surface and underground water.
– Contributing to climate change.
Water Issues
The amount of
water on earth
remains
constant.
World population7.111 billion &
growing
• 783 million people do not
have access to clean water.
• 2.5 billion do not have
access to adequate
sanitation.
• Demand for food, space,
energy and clean water
continues to rise.
What can you do?