The water planet

atmospheric water

continental and sea ice

oceanslakes and rivers

O

Water

HH+

-

Water: we waste it, we pollute it, we take it for granted….

Virtually the most valuable commodity we have (except maybe O2)

Tree = 60% water jelly fish = 90% water

Where has your water come from???

All of the Earth's waters are connected and cleaned by the HYDROLOGIC CYCLE

Water moves through the hydrologic cycle at various speeds.For example:

40,000 years to recycle oceanic water

2 weeks to recycle river water9 to 10 days to recycle atmospheric

water

Energy for the hydrological cycle

• is from the sun (solar power)

• The atmosphere is a heat trap– H2O is a greenhouse gas

• Hydrologic cycle = main global energy redistribution system--thru both the oceans and the atmosphere

Ocean currentsThe Atlantic Gulf stream carries energy at a vast rate from the gulf of Mexico to the Arctic Ocean: all the coal mined in the world in one year could supply energy at this rate for only 12 hours!

(Franks 1984)

The hydrological cycle

Evaporation

• Injects water vapour into atmosphere• Uses 50% of energy at earths surface

(cools the earth’s surface)

The Atmosphere

• only 0.001% of all water • links major water stores

– evaporation– condensation– precipitation

• cold air hold less water than hot air• as hot air rises and cools,

precipitation can form

Effect of vegetation on rainfall

P — precipitation

Effect of vegetation on rainfall

EI—evaporation of intercepted rain

ET—transpiration

Interception loss may be 20 – 40% of total rainfall for forests

Hillslope runoff processes

infiltrationoverland flow

water table

shallow subsurface flowdeep drainage

baseflow

The majority of accessible fresh water is groundwater, water beneath the Earth's surface.

About 10% of precipitation will infiltrate the soil and rock to become groundwater, forming a water table.

Water saturated permeable rock is an aquifer.

Aquifers

Rivers

The Water Balance

May be applied to whole river basins or catchments

SQEP Δ=++

total evapotranspiration

catchment rainfall

river + groundwater discharge

change in soil, groundwater storage

The water balanceQuantifying the hydrological cycle

saturated zone

unsaturated soil

Rainfall

P

Evaporation

EChange in storage

ΔSDischarg

eQ

= +15 mm

= -4 mm

= -6 mm

SQEP Δ=++

15 – 4 – 6 =+5 mm

= +5 mm

0.03% of world’s water is readily available

Not evenly distributed

human water use has increased 4 times in the last 50 yrs!

increasing population and

increasing use per person

~70% used for Agriculture

waste water production=1870 km3 in1980

2300 km3 in 2000

- The BIG water use

1950 -80 world irrigation area tripled

1990: 7% less irrigated area per person than 1980

inc. competition between rural and urban water use

21% of USA crop irrigated by draw-down of W.T

26% of world irrigated area suffers waterlogging and salinization

NOT SUSTAINABLE

The Ogallala Aquifer

Water use

WATER SAVINGS GUIDEWATER SAVINGS GUIDE

Activity:Conservative use- saves water

Normal use -- wastes water

ShowerWetdown/rinse off: 4 gallons

Regular shower: 25 gallons

Brushing teeth Wet brush, brief rinse: 1/2 gal.

Tap running: 10 gallons

Toilets Minimize flushing, low-flush toilets

Old toilet, frequent flushing?!?!

Leaks Report ASAP A small drip: 25 gallons per day

Energy Turn off power Wasting energy wastes water