The water planet

1. oceans lakes and rivers atmospheric water continental and sea ice The water planet Water - O H H +

2. Water: we waste it, we pollute it, we take it for granted…. Virtually the most valuable commodity we have (except maybe O2) You're about 70% Water! Tree = 60% water jelly fish = 90% water Where has your water come from???

3. 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 water 9 to 10 days to recycle atmospheric water

4. 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

5. The 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) Ocean currents

6. The hydrological cycle

7. Evaporation • Injects water vapour into atmosphere • Uses 50% of energy at earths surface (cools the earth’s surface)

8. 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

9. P— precipitation Effect of vegetation on rainfall

10. EI—evaporation of intercepted rain ET—transpiration Effect of vegetation on rainfall Interception loss may be 20–40% of total rainfall for forests

11. Hillslope runoff processes overland flow shallow subsurface flow deep drainage water table baseflow infiltration

12. About 10% of precipitation will infiltrate the soil and rock to become groundwater, forming a water table. The majority of accessible fresh water is groundwater, water beneath the Earth's surface. Water saturated permeable rock is an aquifer.

13. Aquifers

14. Rivers

15. river + groundwater discharge catchment rainfall change in soil, groundwater storage total evapotranspiration The Water Balance May be applied to whole river basins or catchments

16. The water balance Rainfall P = +15 mm Evaporation E = -4 mm +5 mm Change in storage DS = +5 mm DischargeQ = -6 mm Quantifying the hydrological cycle 15 – 4 – 6 = unsaturated soil saturated zone

18. Global Water Supply • 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

20. Irrigation - 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 NOT SUSTAINABLE 26% of world irrigated area suffers waterlogging and salinization

21. The Ogallala Aquifer

26. Water use

27. WATER SAVINGS GUIDE