1. Water Resources, Use, Policy

2. Water Quantity Quantity Sources & Distribution Sources & Distribution Hydrological Cycles & Ecosystem Health Hydrological Cycles & Ecosystem Health Patterns of use & recuperation Patterns of use & recuperation Irrigation Irrigation Dams Dams

3. How Much Water is There? Though most of the earth is covered by water, only 2.6% of all the water is freshwater Though most of the earth is covered by water, only 2.6% of all the water is freshwater If we scaled all the water on the planet to = 100 gallons then all the freshwater would = 9.6 teaspoons! If we scaled all the water on the planet to = 100 gallons then all the freshwater would = 9.6 teaspoons!

4. Distribution of Water

5. Freshwater Cycle

6. Dynamic of Rivers and Ocean Infiltration of seawater depends upon strength of freshwater current and volume Infiltration of seawater depends upon strength of freshwater current and volume In summer season greater seawater penetration In summer season greater seawater penetration In drought years, even greater penetration In drought years, even greater penetration E.g., saltwater wedge from Gulf of Mexico known to penetrate the Mississippii more than 200 miles E.g., saltwater wedge from Gulf of Mexico known to penetrate the Mississippii more than 200 miles

7. Dynamic of Rivers and Ocean Infiltration of seawater can have serious consequences for agriculture, ranching and drinking water Infiltration of seawater can have serious consequences for agriculture, ranching and drinking water Exacerbated by human reduced flows in rivers and watersheds Exacerbated by human reduced flows in rivers and watersheds

8. Flooding is beneficial! Removes salts from soils! Brings in new nutrients!

9. Prevention of Flooding by dykes, levees, channelization, river diversion is expensive and usually leads to increased erosion downstream

10. Humans Living in Flood Zones Billions of $US spent annual on flood relief and insurance Billions of $US spent annual on flood relief and insurance Floods beneficial for agriculture Floods beneficial for agriculture Farming yes, but permanent residences? Farming yes, but permanent residences? Missouri River 1992 Missouri River 1993

11. Freshwater Usage

13. Water for Products (virtual water)

15. Water for Products

16. Water in the West – The Colorado

19. Colorado R. Water is Siphoned Off

20. Colorado R. Water & Agriculture The Imperial Valley of California is one of the major producing regions of fruits and vegetables in the US

21. Delta of the Colorado River: BONE DRY!

22. Stress on aquifers Water shortage

23. Irrigation Takes water from rivers or aquifers Takes water from rivers or aquifers In US > 21 million hectares In US > 21 million hectares Increased rate of water loss to evaporation Increased rate of water loss to evaporation Costs do not include depletion of freshwater resources Costs do not include depletion of freshwater resources

24. Depletion of aquifers Ogallala Aquifer Should we be irrigating the most arid lands in the USA???

25. Soybeans require ca. 25 inches (=.64 m) of water when grown on arid soils A hectare is 10,000 sq. m each hectare of soybeans requires 6,400 m 3 of water 100,000’s hectares of soybean agriculture in arid western US (e.g., eastern Oregon, Nevada, Colorado, Wyoming, etc.)