1. WATER resources AP Environmental Science
The amount of water in the earth is constant

2. Imporantant Resource
Water is essential and maintains all life and ecosystems
It regulates the temperature of the planet
Redistributes heat
Cycles essential nutrients through land, air and all living things.

3. Renewable Resource
Fresh water is a renewable resource because of the hydrologic cycle which returns water to both surface and groundwater sources from the atmosphere.

4. Earth’s Distribution of Water
Figure 15-01
Title:
Only 2.5% of Earth's water is fresh water.
Caption:
Of that 2.5%, most is tied up in glaciers and ice caps. Of the 1% that is surface water, most is in lakes and soil moisture. Data from United Nations Environment Programme (UNEP) and World Resources Institute.
Notes:
Keywords:
fresh water, streams, rivers, groundwater, oceans, atmosphere

5. Natural Capital: Surface Water
Fresh water that exists above ground
Streams
Rivers
Ponds
Lakes
Wetlands
Watershed
Area of land drained by a river system
Drainage basin

6. Natural Capital: Surface Water
Almost ¾ of all water used in the U.S. comes from surface water and is used for electric power generation, municipalities, industrial use, and irrigation
South Platte River, Colorado

7. Natural Capital: Surface Water
Productivity classification
Oligotrophic
Low nutrients
High oxygen
Eutrophic
High nutrients
Low oxygen
Eutrophication usually results from human-caused excessive nutrient pollution.

8. Natural Capital: Wetlands
Surface water systems in which the soil is saturated with water
Generally feature shallow standing water with lots of vegetation
Marsh
Swamp
Bog

9. Natural Capital: Wetlands
Vernal Pool
Seasonal wetlands containing water only at a specific time of the year.
Wetlands are extremely valuable as habitat for wildlife
Wetlands provide important ecosystem services
Slowing runoff
Reducing flooding
Recharging aquifers
Filtering pollutants

10. Natural Capital: Wetlands
Extensive damage of wetlands has occurred throughout the U.S.
Less than half of all wetlands remain
Ramsar Convention on Wetlands (1971)
Seeks protection of wetlands worldwide

11. Natural Capital: Ground Water Systems
Water beneath Earth’s surface, held within the pores of soil and/or rock.
Account for ¼ of all water used in the U.S.
Supplies almost ½ of all drinking water
Important source of irrigation for Midwest

12. Natural Capital: Ground Water Systems
Evaporation and transpiration
Evaporation
Stream
Infiltration
Water table
Unconfined aquifer
Confined aquifer
Lake
Well requiring a pump
Flowing
artesian well
Runoff
Precipitation
Confined
Recharge Area
Aquifer
Less permeable material
such as clay
Confirming permeable rock layer

13. Natural Capital: Ground Water Systems
Aquifers
Underground reservoir contained in porous, sponge-like formations of rock, sand or gravel.
Largest know aquifer is the Ogallala, located under 8 U.S. Great Plains states

14. Natural Capital: Ground Water Systems
unconfined aquifer is an aquifer with a permeable water table.
confined aquifer is bounded above and below by less permeable beds of rock where the water is confined under pressure.
Some aquifers are replenished by precipitation; others are not.

15. Natural Capital: Ground Water Systems
As aquifers are withdrawn, they recharge VERY slowly; average rates are only about 1 m per day.

16. Natural Capital: Ground Water Systems
Water Table
The upper limit of groundwater held in an aquifer
Drops when aquifers are overdrawn
Result= becomes more difficult and expensive to extract.

17. Natural Capital: Ground Water Systems
In parts of Mexico, India, China and many Asian and M.E. nations, water tables are falling 3-10 feet per year.
In coastal areas, saltwater can intrude, making the water undrinkable and land can subside, creating sinkholes

18. Sustainability
ONLY if water is used and managed sustainably can water be realized as a renewable resource.
Currently, in many industrial nations, concerns over water quantity dominate
In developing countries, concerns over both water quantity and quality persist

19. Where Does It Rain?
Humans are not distributed across the globe in accordance with water availability.

20. Where Does It Rain?
A growing number of heavily populated countries are located in arid lands

21. Global Water Conflicts
Two main factors for water shortage: dry climate and too
many people. Many people live in hydro poverty – can’t afford clean water.

22. Sharing Water Resources Among Countries

23. Potable Water Safe Drinking Water
Nearly 1 billion people do not have access to safe drinking water
80% of human illness result from poor drinking water
Increasing populations put additional stress on water supplies

24. What is the Trend? Over the last century
Human population has increased 3x
Global water withdrawal has increased 7x
Per capita water withdrawal has increased 4x
About one-sixth of the world’s people don’t have easy access to safe water
Most water resources are owned by governments and are managed as publicly owned resources

25. Usage?

26. Annual Precipitation of the Continental U.S.
A person needs about 1 gallon water/day for hydration
In the US each person uses about 188 gallons/day
An additional 657 gallons/person/day are used for irrigation, industrial use.
Total per capita use is about 2000 gal/person/day
US has highest per capita water withdrawal, followed by Canada, Australia, Russia, Japan

27. Too Little Water Problems in the West Dry climate Drought Desiccation
US has plenty of water.
Much of it is in the wrong
place at the wrong time.
Most serious problems are flooding, pollution, and occasional urban shortages
Acute shortage
Adequate supply
Shortage
Metropolitan regions with population greater than 1 million

28. Too Little Water
Growing Problem

29. Population Growth Supply & demand are in growing conflict –
supply is finite
water management driven by values and needs
In the western US, irrigation makes up 85% of all water use
50% to grow food for livestock
35% to grow crops
Not sustainable…cost of water is heavily subsidized by the federal government

30. Supply and Demand
Agriculture uses approximately 70% of the Earth’s annual fresh water withdrawn from our streams and rivers

31. Supply and Demand
Amount of land currently being irrigated has doubled in the last 50 years to meet the demand for food.

32. Supply and Demand Most irrigation remains highly inefficient
Crops end up using only 40% of the water applied by “flood and furrow” methods

33. Supply and Demand
Over-irrigation leads to waterlogging and the salinization of agricultural lands
World-wide, about 15-35% of water withdrawals for irrigation are thought to be unsustainable.

34. Supply and Demand Industry Residential
Accounts for approximately 20% of Earth’s annual fresh water use
Residential
Accounts for approximately 10% of Earth’s fresh water use.

35. Bottled Water
Bottled drinking water production now represents a significant groundwater extraction and depletion problem
Nestle, Pepsi-Cola, Coca-Cola have begun extracting ground water, bottling and selling it for a profit, and then moving on , leaving the community from which the water was taken with a degraded resource base.

36. Bottled Water
Bottled water exerts substantial ecological impact because it is heavily packaged and transported long distanced using fossil fuels.
Bottled water is not demonstrably safer or healthier than tap water
In fact, often the source is not as strictly regulated as drinking water by the EPA

37. Supply and Demand Change in land use changes permeability
Areas with 15 to 75 percent impervious surface are characterized as moderately developed.
Areas with greater than 75 percent impervious surface are considered urban or highly developed.

38. Supply and Demand
Areas with greater than 10% impervious surface have been proven to have a negative affect on groundwater and storm water.

39. Water Rights Water collectively belongs to the public
Cannot be owned by individuals
Individuals or groups may be granted rights to use water
Legal authorization to use a predefined quantity of public water for a designated purpose.
Irrigation, domestic water supply, power generation

40. Water Rights
State law requires certain users of public waters to receive approval from the state prior to using water.
Any use of surface water which began after 1917 requires a water-right permit.
Withdrawals of underground water from 1945 requires a water-right permit.