1. Chapter 12
Water Resources

2. Usable Water is Rare 70% of the Earth’s surface is covered in water
3% of the water on the planet is fresh water
Less than 1% of all water is easily available for use by humans
Most fresh water is locked in glaciers and ice caps
Accessible forms include groundwater, surface water, and atmospheric water

4. Groundwater Is water found underground, usually in aquifers
Water Table
Uppermost layer where groundwater fully saturates the spaces within rock
Also called the groundwater surface
Groundwater Recharge
Area where water can move through the soil and enter an aquifer

6. Aquifers Are spaces within layers of rock that store water
Unconfined aquifers
Water can enter or leave easily
Top layer is loose soil or permeable rocks
Confined aquifers
Water cannot enter or leave easily
Surrounded by a layer of clay or solid rock
Can sometimes be refilled if there is an opening called a recharge area

7. Removing Groundwater Springs Wells Artesian Wells
Areas where groundwater naturally pushes up out of the ground
Wells
A hole is drilled to reach an aquifer and pump the water to the surface
Artesian Wells
Form from drilling a hole into a confined aquifer
Pressure causes water to rise to the surface

8. Groundwater Removal Problems
Removal rate exceeds recharge rate
Overall aquifer level drops, can dry up
Springs no longer function
Sinkholes can form

11. Problems with Groundwater Removal
Cone of Depression
Rapid pumping removes water near a well more quickly
Well dries up

13. Problems with Groundwater Removal
Saltwater Intrusion
Happens in wells near salt water
Decreased water pressure in aquifer allows saltwater to enter

14. Surface Water Is fresh water that exists above ground
Streams, rivers, ponds, lakes, wetlands
Most accessible and most highly used form of fresh water
Drinking and washing
Agriculture
Transportation
Can create fertile soil
Rivers flood, deposit sediment in the flood plain

15. Atmospheric Water
Is water that has evaporated into and moves throughout the atmosphere
Is affected by seasons and climate events
El Niño
Global warming
Too much causes floods
Lack causes drought

16. Atmospheric Water Replenishes groundwater and surface water
Absorption is affected by urbanization
More impermeable surfaces means less water seeping into the ground and more surface flooding

17. Managing Water Resources
Moving water to where it’s needed
Using water to generate work
Hydropower
Electricity
Storing water for future use
Reservoirs
Rain barrels

19. Levees Are enlarged, elevated banks built on the sides of rivers
Are designed to control flow and prevent flooding
Alter sediment flow which reduces enrichment of flood plains

21. Dikes Are levees for ocean coasts
Used in areas where usable land lies below sea level

22. Dams Are barriers across rivers or streams that restrict water flow
Create reservoirs of water
Can create hydroelectric power
Disrupt sediment flow, communities and ecosystems

23. Aqueducts Are canals or ditches that transport water
Removes water from ecosystems
Can lose up to 50% of their water to evaporation
Can cause political problems
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