1. 1 Water Use and Management

2. 2 Water as a Resource  Covers 71% of earth’s surface  Important properties –Polar –Moves easily –Changes temperature slowly  Moderates earth’s climate  Protects living things from temperature fluctuations

3. 3 Available Water  Total = 326 million cubic miles  97% in oceans  2.997% is locked up in ice caps and glaciers  0.003% is easily accessible –Soil moisture –Groundwater –Water vapor –Lakes –Streams

4. 4 Surface Water  Runoff flows into streams, lakes, wetlands and reservoirs  A watershed or drainage basin www.canaanvi.org/assistance/ watershed.asp

5. 5Groundwater  Precipitation infiltrates and percolates –Pores, fractures, crevices, etc.  Zone of aeration - Upper soil layers that hold both air and water.  Zone of saturation is at a depth were ground is filled with water  Top of this zone is water table –Falls and rises with weather

6. 6 Water Compartments

7. 7 Groundwater  Aquifers - Porous layers of sand, gravel, or rock lying below the water table. –Artesian - Pressurized aquifer intersects the surface. (Water flows without pumping)  Recharge Zones –Recharge rate is often very slow.  groundwater is being faster then it can be replenished

8. 8 Groundwater

9. 9 Objectives and Warmup: 12/1/10  Objectives: –Explain why water is not equally distributed throughout the world.  Warmup: –What makes water not equally distributed throughout the world?

10. 10 Use of Fresh Water United States Agriculture Power plant cooling Industry Public China Agriculture Industry Public

11. 11 Water Use Globally   70% soaked up by agriculture (mostly in the form of irrigation)   Industry accounts for 23%   Domestic use (household, drinking water, sanitation) accounts for about 7%

12. 12 Water Use  According to the UN, the average person needs a minimum of: –1.3 gallons of water per day to survive in a moderate climate at an average activity level –13 gallons for drinking and cooking, bathing and sanitation  The average person in the United States uses between 80-100 gallons per day for drinking, cooking, bathing, and watering their yard.

13. 13 FRESHWATER SHORTAGES  Estimated 1.5 billion people lack access to an adequate supply of drinking water. –Nearly 3 billion lack acceptable sanitation. –Globally, water supplies are abundant, but, along with capital resources, are unevenly distributed.

14. 14 Freshwater Shortage Causes  Dry climate  Drought- a period in which precipitation is lower & evaporation is higher than normal  Desiccation- drying of the soil as a result of deforestation & overgrazing  Water stress- more people relying on same amount of water

15. 15 Global Precipitation Patterns Wright and Nebel, 2002. Michael D. Lee Ph.D. Geography and Environmental Studies

16. 16 Rainfall Distribution  Rain falls unevenly over the planet  Three factors control rainfall –Global atmospheric circulation-creates regions of high air pressure and low rainfall –Prevailing Winds-bring moisture to land from ocean; areas far from oceans are usually dry –Topography-mountains act as cloud formers and rain catchers

17. 17 Rain Shadow Effect

18. 18 Objectives and Warmup: 12/2/10  Objectives: –Analyze how national and local water use are distributed and used throughout the US.  Warmup: –Calculate the per capita water use of Montana:  Population 902 in thousands  Water use 8290 in millions

19. 19 Increasing the Supply of Freshwater  Dams and reservoirs  Tapping groundwater supplies  Desalinization  Towing icebergs  Water conservation

20. 20 Dams and Reservoirs  Advantages: –Produce electricity –Irrigate land below the dam –Divert water to cities, towns and rural areas –Recreation

21. 21 Dams and Reservoirs Cons  Environmental Costs –Upsets natural balance of water systems –Croplands downstream are deprived of nutrient rich silt –Evaporation  Ecosystem Losses –Loss of wildlife habitat –Migration and spawning of fish disrupted –Flooded land destroys forests or cropland  Displacement of People

22. 22 Colorado River Basin  Diversion of water from Colorado River –Disputes between AZ, CA, Mexico –Dams trap silt--- more fertilizer needed –High levels of NaCl- salinization

23. 23  Three Gorges Dams in China is forcing relocation of 1.2 million people

24. 24 Tapping Groundwater Supplies  About ½ of the drinking water in the US is pumped from aquifers  Advantages –Year-round use –Renewable if not overpumped or contaminated –No evaporation losses –Often less expensive

25. 25 Tapping Groundwater Supplies  Disadvantages –Water table lowering –Overpumping –Sinking of land (subsidence) when water removed –Chemical contamination –Saltwater intrusion into drinking water supplies near coastal areas

26. 26 Cone of Depression and Saltwater Intrusion

27. 27 Ogallala Aquifer  Underlies 8 states from SD to TX  Held more water than all freshwater on Earth  Water shortages

28. 28 Desalinization  Removing salt from sea water: reverse osmosis –currently 3-4x more expensive

29. 29 Towing Icebergs  Carry fresh water to places that need it –How can it be done? Would it be economically sound?

30. 30 Water Efficiency and Conservation  Change in personal habits  Fix leaky pipes  Water–saving toilets, faucets, & shower heads  Plant drought–tolerant vegetation in residential communities located in arid & semi–arid areas  Increase efficiency of irrigation –drip irrigation, computer monitoring, center-pivot  Use recycled water –treat gray water from showers, washing machines for reuse  Education

31. 31

32. 32