Transcript Reservoir Average residence time of a water

Water Cycle and the Distribution
of Water
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.
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!
What happens to rain fall?
Of 100 drops of rain
2 Goes into
“ground water”
2 make it into our faucets
66 drops go back into
the sky
Within a week
30 of them go into creeks and rivers
But… how do those 66 drops make
it back? IN TEXAS..
2 Goes into
“ground water”
2 make it into our faucets
66 drops go back into
the sky
Within a week
30 of them go into creeks and rivers
But… how do those 66 drops make
it back? IN TEXAS..
2 Goes into
“ground water”
2 make it into our faucets
33 drops evaporate
directly
33 drops make it via
TRANSPIRATION
30 of them go into creeks and rivers
Atmosphere
Source: US Geological Survey www.usgs.gov
Million dollar question.
Are these % of where water is
static? Could they change?
• If you listen to news, you would know that
most scientists that study it know the
ocean level has risen 1-2ft in the past 50
years, and will rise several more feet in
the next 50 years. What does this do to
our percentages?
• In the “Ice age” … how might these
amounts be different?
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
City use
• Drinking
water
• Sanitation
• Lawn
water
• Car
washing
Farm use
• Crops, etc.
Industry use
• making
energy.
• Cooling plants
• Used in the
manufacturing
process
Where do we get the water we use?
Three main sources:
Rivers
Ground water
Lakes (man made reservoirs)
Sources rarely used:
Rain catchers/harvesters (mainly at homes)
Oceans – it has to be desalinated (taking salt
out is expensive)
Sources never used for human needs:
Glaciers, soil water, plant and animals
Assignment tomorrow
Story of a water molecule.
• 1-2 pages, tell the story of
– 1 water molecule’s unique experience
– A group that gets seperated and comes back
together.
• Will need to include at least 15 changes, and
convince me you have an in depth
understanding of the complexity of the water
cycle
– Changes, places, timing, etc.