1. Water Resources All waterFresh water Readily accessible fresh water Oceans and saline lakes 97.4% Fresh water 2.6% Groundwater 0.592% Ice caps and glaciers 1.984% Lakes 0.007% Soil moisture 0.005% Biota 0.0001% Rivers 0.0001% Atmospheric water vapor 0.001% 0.014% Oceans Ice Lakes Soil moisture 77 trillion gallons/person 240,000 gallons/person

2. Evaporation and transpiration Evaporation Stream Infiltration Water table Infiltration Unconfined aquifer Confined aquifer Lake Well requiring a pump Flowing artesian well Runoff Precipitation Confined Recharge Area Less permeable material such as clay Confirming permeable rock layer Watershed, water table, aquifer

3. Increasing Demand for Water 5,500 5,000 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500 190019201940196019802000 Water use (cubic kilometers per year) Total use Agricultural use Industrial use Domestic use Year

4. Use of Water Resources  In U.S., 2000 gallons/day/person  Agriculture - 700 gallons  Industry/commercial - 1200 gallons  Industry/commercial - 1200 gallons  Home - 100 gallons - 3 X world average - 20 X developing nations  Home - 100 gallons - 3 X world average - 20 X developing nations United States Industry 11% Public 10% Power cooling 38% Agriculture 38%

5. Problem: Too Little Water  Dry climate  Drought - 40% of people  Drought - 40% of people Acute shortage Adequate supply Shortage Metropolitan regions with population greater than 1 million

6. Problem: Too Much Water  Natural phenomena Floodplain Levee Flood wall Dam Reservoir  Renew and replenish  Aggravated by human activities

7. Maintaining Adequate Supplies  Increase current supply  Reduce pollution  Use water more efficiently

8. Tapping Groundwater  Year-round use  No evaporation losses  Often less expensive  Potential Problems!

9. Problems with Using Groundwater  Water table lowering  Depletion  Subsidence  Saltwater intrusion

10. Ogallala Aquifer WYOMING SOUTH DAKOTA NEBRASKA COLORADO KANSAS OKLAHOMA NEW MEXICO TEXAS 0100 Miles Kilometers Less than 61 meters (200 ft) 61-183 meters (200-600 ft) More than 183 meters (600 ft) (as much as 370 meters or 1,200 ft. in places) 0160

11. Lowering the Water Table Initial water table Cone of depression Original water table Lowered water table

12. Groundwater Overuse Groundwater Overdrafts: High Moderate Minor or none

13. Ground Subsidence Subsidence: High Moderate Minor or none

14. Major irrigation well Well contaminated with saltwater Saltwater Intrusion Normal Interface Fresh groundwater aquifer Interface Salt water Sea Level Water table Saltwater Intrusion

15. Using Dams and Reservoirs to Supply More Water Large losses of water through evaporation Large losses of water through evaporation Flooded land destroys forests or cropland and displaces people Flooded land destroys forests or cropland and displaces people Downstream flooding is reduced Downstream cropland and estuaries are deprived of nutrient-rich silt Downstream cropland and estuaries are deprived of nutrient-rich silt Reservoir is useful for recreation and fishing Can produce cheap electricity (hydropower) Migration and spawning of some fish are disrupted Provides water for year-round irrigation of cropland

16. Transferring Water from One Place to Another North Bay Aqueduct North Bay Aqueduct South Bay Aqueduct South Bay Aqueduct California Aqueduct CALIFORNIA NEVADA UTAH MEXICO Central Arizona Project Colorado River Aqueduct Los Angeles Aqueduct Shasta Lake Sacramento Fresno Phoenix Tucson ARIZONA Colorado River Sacramento River Sacramento River San Francisco Los Angeles San Diego  Watershed transfer  California Water Project  Central Arizona Project

17. Converting Salt Water to Fresh Water and Making it Rain  Distillation desalination  Reverse osmosis desalination  Desalination is very expensive  Cloud seeding

18. Using Water More Efficiently  Reduce losses due to leakage (e.g., Boston)  Reform water laws (use it or lose it)  Improve irrigation efficiency  Improving manufacturing processes  Water efficient landscaping  Water efficient appliances

19. Solutions: Achieving a More Sustainable Water Future  Efficient irrigation  Water-saving technologies  Improving water management

20. Gravity Flow (efficiency 60% and 80% with surge valves) Water usually comes from an aqueduct system or a nearby river. Drip or Trickle Irrigation (efficiency 90-95%) Above- or below-ground pipes or tubes deliver water to individual plant roots. Center Pivot (efficiency 80% with low-pressure sprinkler and 90–95% with LEPA sprinkler) Water usually pumped from underground and sprayed from mobile boom with sprinklers. Irrigation Methods

21. Saving Water in the Bathroom

22. Gray Water and Dual Systems