1. Water Resources Q: What water can we use?
A: 97.4% of Earth’s water is salt
2.5% of Earth’s water is frozen
0.014% is available for human use

2. Earth’s Water System Fresh water is found in 2 locations:
1) Surface Water
- water that remains above ground & does
not evaporate
- examples- streams, lakes, wetlands
- watershed/drainage basin
- area that funnels water into surface
locations

3. Groundwater Features

4. 2) Groundwater - water that permeates downward below the
soil’s surface
Groundwater Terms
zone of saturation- underground areas filled with
water.
water table- top of the zone of saturation
zone of aeration- porous areas available for H2O
aquifers- areas where groundwater flows

5. Groundwater Features

7. Saltwater Intrusion

8. Global Water Use
- 70% is used for agriculture
- 20% is used for industry
- 10% is for residential use

9. Causes of Water Shortages
Drying climates
Increased droughts
Desiccation
- drying due to human activities
Water stress
- over-consumption due to population growth
Unequal distribution

11. Solutions to water shortages
Build dams & reservoirs
Transport surface water to needy areas
Withdraw more groundwater
Desalination (converting salt to fresh)
Increase water conservation
Import food

12. Aspects of Dam & Reservoir Usage
Pros
1) Controls floods
2) Produces cheap hydroelectric power
3) Supplies year round irrigation
4) Provides recreational areas
5) Increases runoff for human use

13. 1) Increases water loss through evaporation
Cons
1) Increases water loss through evaporation
2) Relocation of people & wildlife
3) Disrupts spawning of fish
4) Slows movement of nutrient-rich silt downstream
5) Decreases amount of water returning to oceans
6) Increase salinization downstream

14. The Aral Sea Disaster

17. - water supply year round - no evaporation loss - less expensive
Tapping Groundwater
Pros
- water supply year round
- no evaporation loss
- less expensive
- provides 1/3 of world’s water (51% in U.S.)
Cons
- decreases water table, depletion of aquifer
- aquifer subsidence (sinking of land)
- salt water intrusion (coastal areas)
- chemical contamination of groundwater
- reduces stream flow

18. Desalination - converting salt water into fresh water 2 Ways:
1) Distillation
- heating to evaporation & collecting condensed
water
2) Reverse Osmosis
- passing salt water through membranes that
catch salt molecules
Problems
- costly (2-3x more expensive)
- creates large amounts of wastewater

19. Other Options for Water
1) Cloud Seeding
- creating rain clouds by adding chemicals
- difficult in dry regions (duh, no clouds)
- increases pollutants in air & water
2) Towing Icebergs
- mostly an idea
- technology is unavailable

20. Water Conservation ? Why are we wasting water ?
1) Water subsidy policies
- makes water cheap
- creates false sense of water abundance
2) Current water laws
- allows anyone along a river rights to it
3) Fragmented watershed management
- too many groups overseeing same areas

21. Irrigation Conservation
Problem
Over 50% of irrigation water is wasted.
Flood irrigation is primary method.
Solution
1) Efficient sprinkler systems
- modern sprinklers are 80-90% efficient
2) Use soil moisture detectors
- allows for irrigation only when needed
3) Drip irrigation systems
- use of pipes to deliver small amounts of water
% efficient
- expensive
4) Use treated waste water for irrigation (gray water)

22. Commercial & Residential
Conservation
1) Reuse water for irrigation
2) Raise water prices
3) Monitor water leaks
4) Use plants that require
less water

23. Flooding Issues - Provides flood control - Creates fertile soil
Natural Floodplain Benefits
- Provides flood control
- Creates fertile soil
- Recharges groundwater
Problems
- Construction of dams & levees in floodplains
- Removal of vegetation in floodplains for urban use
- Diversion of streams in floodplains
*Create dangerous situations during unusual rainfalls*