1. Water Sources Increasing Water Availability Water Uses Future of Water
Water Resources
Water Sources
Increasing Water Availability
Water Uses
Future of Water

2. Water Sources

3. Water Sources
Water is abundant but usable water is rare. Of the portion of water that is freshwater, ¼ is below groundwater, less then ¾ is locked in ice, glaciers, the atmosphere and in the soil. Therefore, less than one percent is accessible for human use. Freshwater Initiative

4. Groundwater Aquifers are sources of usable groundwater.
Unconfined aquifers are rapidly recharged by water that percolates downward from the land surface. The water table marks the upper limit of the aquifer.
Confined aquifers are capped by an impermeable layer of rock or clay, which can cause water pressure to build up underground.
Artesian wells are formed when a well is drilled into a confined aquifer and the natural pressure causes water to rise toward the surface.

5. Groundwater Recharge
Groundwater recharge is through precipitation percolating through soil.
Confined aquifers can be recharge through openings in the land called recharge areas. It generally takes 10,000 – 20,000 years to recharge.
The rate of recharge is dependent on geology and precipitation rates, and affects the long term availability for water.

6. Ogallala Aquifer Groundwater of the world
The Ogallala aquifer in the Great Plains
The largest aquifer in the U.S.
A confined aquifer with slow recharge
Predicted, at currents rates of water withdrawal and recharge, to run out of water this century
Waters most of our ‘breadbasket’

7. Impacts on Groundwater
When water is rapidly withdrawn the following may occur:
Cone of depression – region is which there is no longer any groundwater, causing the main well and surrounding wells to dig deeper to obtain water
Saltwater intrusion – occurs with water is rapidly withdrawn from aquifers that are adjacent to coastlines. As water is withdrawn, the pressure in the aquifer is reduced allowing for the infiltration of saltwater in the region.

8. Surface Water Surface Water of the World
Civilizations typically settled along the banks of rivers because of transportation, fertile soils of the floodplains.
Largest rivers by volume include the Amazon, the Congo and the Yangtze
Lakes are classified by their nutrient loads:
Mesotrophic, oligotrophic and eutrophic
Largest lakes include (in order by volume):
Caspian Sea (salty lake), Baikal, Tanganyika,Superior, Michigan, Huron, Victoria
Wetlands
Absorb and retain water, act like a spnge/filter
Largest is the Pantanal of Brazil, followed by the Everglades

9. Atmospheric Water
Atmospheric water is essential to the distribution of water across the globe.
Under drought situations, heavy rainstorms can create flashfloods. These floods may also be created by increases in impermeable surfaces.

10. Water uses

11. Water Uses
On average it is estimated that 70% of freshwater is used for agriculture, 20% for industry and 10% for household uses.
Over the past 50 years, agriculture output has kept up with the human population but the water use has more than doubled.
In the U.S., 1/3 of freshwater is used for agriculture

12. Irrigation
The greatest potential for conserving water is by changing irrigation practices
Irrigation techniques include:
Furrow – easy and inexpensive. Trenches are filled with water that seeps through the soil. Has 65% efficiency.
Flood – floods the entire field; more disruptive to plant growth. Has 70-80% efficiency
Spray – more expensive and energy consuming; sprinkler devices are used to spray water across fields. Has 75-95% efficiency
Drip – water is slowly dripped from a hose; reduces weed growth Has 95% efficiency.
Hydroponic agriculture – uses up to 95% less water

13. Industrial Uses Water is required for
Generating electricity (in U.S. 50%)
Cooling machinery
Nuclear reactors and power plants; can cause thermal pollution
Refining materials
116 gallons (440 L) per 1 kg of copper
Paper production
Requires 33 gallons (125 L) per 1 kg of paper

14. Household Uses Indoor uses Outside Toilet Laundry Bathing Faucets
Leaks
Cooking and drinking
Outside
Watering lawns
Washing cars
Swimming pools

15. Increasing Water Availability

16. Levees An enlarged bank built up on each side of a river
Prevents flooding into floodplains where humans have established residency and industry
Reduced fertility of floodplains
Sediments are not deposited throughout the length of the river but at the mouth of the river
Force greater flooding downstream
Encourages development in floodplains

17. Dikes
Similar to levees but are typically built to prevent the ocean from flooding adjacent land
Common in Europe
Pumps water back out to the ocean. Originally powered by windmills

18. Dams A barrier that runs across a river to control the flow of water
Water that collects behind the dam (upstream) is called the reservoir
Dams hold water for human consumption, energy generation (hydroelectric power), flood control and recreation.
There are approximately 845,000 dams in the world and 82,642 in the U.S.
In the U.S., most dams were constructed for flood control and recreation (~56%)

19. Financial, social and environmental costs
Ex. Three Gorges Dam across the Yangtze River
Took 13 years to construct, 2 years to fill with water
Displaced 13 cities, 140 towns, 1350 villages and forced 1.3 million people to relocate
Increased pollution and effects of eutrophication

20. Dams Interrupts the natural flow of water
Blocks migration of fish like salmon, which can have a cascading effect on the other organisms that depend on them.
Reduces water flow down stream
Shifts seasonal flooding as operators release excess water
Concentrations pollution in the reservoir

21. Aqueducts
Canals, channels or ditches that carry water to a new location
Can lose as much as 55% of the water through evaporation
New York (Catskills) and L.A. (Colorado river) rely on aqueduct for water
Construction fragments habitats
May be built underground to reduce water loss
Diverts water from natural course

22. Water Diversion Projects
China
Diversion of water from Bangladesh to India
India will gain 170 billion liters of water a year
May increase movement of saltwater upstream of estuaries
Reduce flow severely restricting habitat downstream
Aral Sea Diversion by USSR in ‘50s (Kazakhstan/Uzbekistan)
Increased salinity in Aral sea due to reduced freshwater input
Surface area reduced by 60%, increased dust storms, erosion and pesticide residues
Affected climate, summers are hotter and winters are colder

23. Desalination Processes that remove salt to obtain freshwater
50% of the water in the Middle East is produced by desalinization
Distillation – uses heat to boil water, leaving salts behind, and then capture and condense the steam.
Reverse osmosis – Pressure is applied to push water through a semipermeable membrane which leaves salt behind. More efficient and often less costly then distillation, however, waste brine can contaminate region

24. Water Availability Varies greatly around the world
Middle East and North Africa represent 5% of the world’s population but have less than 1% of the world’s freshwater
1.2 billion people live in regions with scarce water
Water Burden

25. Future of Water

26. Water Ownership Who has rights?
Regional and national government
Private and public ownership
Conflicts are created over water rights
Bangladesh-India
Iran-Iraq
Florida-Georgia
Arizona, New Mexico, California, Mexico
Chile and free-market systems

27. Water Conservation
Federal standards were set in for improved efficiency:
Double flush toilets
Reduce volume toilets
Reduced flow showerheads
Front-loading washing machines
High efficiency washing machines
Xeriscaping of land
Recycling of water (gray water systems)
Treated wastewater for drinking water

28. Protecting Wetlands
Wetlands provide many vital ecological and economic services
The U.S. has lost up to 80% of wetlands since 1962 to today.
To reduce loss, mitigation banking was put into effect
Wetlands may be destroyed as long as an equal area of the same type of wetland is created or restored

29. Florida Everglades
U.S. Army Corps of Engineers straightened the Kissimmee River in 1960’s to provide ample water to growing cities and agricultural lands
Ag lands led to increased P in the everglades leading to eutrophication
Decreased flow of water led to increased wildfires, loss of habitat and biodiversity (90% of the birds, % of turtles)
$7.8 billion and 20 years later restoration began
…but is still fighting big sugar and anti-environmental movements

30. Protecting Rivers and Lake
Lakes
Invasion by non native species (zebra mussels, asian carp)
Eutrophication
Water diversions
Filling-in for development
Rivers
Damming
Interfer with migratory fish, esp. salmon
Diversions