1. DO NOW
Pick up notes and Review #32.
Turn in Review #31.

2. REVIEW #30

3. REVIEW #30

4. REVIEW
What are the advantages and disadvantages of each energy source?
Fossil fuels?
Nuclear?
Wind?
Solar?
Biomass?
Geothermal?
Hydroelectric?

5. Water, water everywhere but not a drop to drink
WATER RESOURCES
Water, water everywhere but not a drop to drink
SES6. Students will explain how life on Earth responds to and shapes Earth systems.
a. Relate the nature and distribution of life on Earth, including humans, to the chemistry and availability of water.

6. EARTH’S WATER SUPPLY

7. EARTH’S WATER SUPPLY Earth’s Water Supply:
About 70% of the Earth's surface is water-covered.
Oceans hold about 97% of the planet’s water.
Freshwater is 3% and includes:
Glaciers and ice caps (2%)
Rivers and lakes
Groundwater & soil moisture
Aquifers
Water vapor in the air
Plants and animals
All that water would fit into that tiny ball that has a diameter of about 860 miles.

8. WATER ON THE SURFACE Water on the surface: Lakes, Swamps, and Rivers
Amount of water in rivers and lakes is always changing due to inflows and outflows.
20% of all unfrozen surface water is in Lake Baikal in Siberia (638 km long, 80 km wide, 1,620 m deep) – deepest and oldest lake on Earth
Another 20% is in the Great Lakes.

9. WATER FROM THE SURFACE

10. WATER FROM THE GROUND
Groundwater: Water that is stored beneath surface - more like water in a sponge than a “river”.
Unsaturated zone: upper layer of soil – water is present but soil not “soggy”
Saturated zone: cracks and spaces between rock particles hold water
Aquifers: underground storage

11. WATER FROM THE GROUND

12. AQUIFERS STORE GROUNDWATER
Underground layers of rock that are saturated with water.
Can be brought to the surface through natural springs or by pumping.
50% of all drinking water comes from aquifers.

13. WE USE WATER…. LOTS OF IT!

14. DIFFERENCES IN WATER USAGE

15. DIFFERENCES IN WATER USAGE

16. GROWING POPULATIONS USE MORE WATER

17. TOO LITTLE FRESHWATER
About 41% of the world’s population does not have enough freshwater.
Many parts of the world are experiencing:
Rivers running dry.
Lakes and seas shrinking.
Falling water tables from over pumped aquifers.

18. GROUNDWATER WITHDRAWALS
Groundwater use is growing - mostly from agriculture.
Industry and mining also use water.

19. GROUNDWATER DEPLETION
Groundwater depletion: long-term water-level declines caused by sustained pumping.
Leads to:
Lowered water tables (water is harder to get to).
Increased cost for consumers.
Land subsidence – loses support sinks.
Deterioration of water quality.
Saltwater intrusion near coasts.

20. SALTWATER INTRUSION Occurs where water table near the coast drops.
Drilling for freshwater along a coast reduces groundwater flow toward coastal area.
Saltwater then is drawn toward the freshwater zones in the aquifer.
Saltwater intrusion decreases freshwater storage in the aquifers.

21. GROUNDWATER CONTAMINATION
Groundwater contamination: When man-made products (gasoline, oil, road salts, chemicals, etc.) get into the groundwater and cause it to become unsafe for human use.
Sources include:
Storage tanks
Septic tanks
Landfills
Hazardous waste
Industrial discharge

22. GROUNDWATER CONTAMINATION

23. DIVERTING WATER
Transferring water can make unproductive areas more productive but can cause environmental harm.
Promotes investment, jobs, and strong economy.
It encourages unsustainable use of water in areas water is not naturally supplied.

24. STORING WATER IN DAMS Benefits: Produce cheap electricity
Stores water for drinking
Provide year-round water for irrigating cropland
Holds excess runoff
Slowly release the water for several days
Reduces flooding downstream
Recreation and fishing uses

25. STORING WATER IN DAMS Problems: Displaces people
Destroys ecosystems to build dams
Disrupts aquatic systems
Risk of failure
Life cycles of some fish species disrupted
Downstream estuaries and cropland robbed of nutrients

26. REVIEW How does increases in population affect the water supply?
Increased demand
Increased pollution
Increased waste
All the above

27. TO DO
Do Review #32.
Work on The Energy Resource Scavenger Hunt or the Renew-A-Bean lab.