1. Resources, Use, and Pollution
Essential Question: What is the current and future status of our clean water supply?
Day 1 1

2. Water Resources Humans use water for:1
Water Resources
Humans use water for:
Drinking
Agriculture
Sanitation
Travel
Entertainment
Essential for life – can go 3 weeks without food, but only 3 days without water
Need freshwater! (not salt water)
Day 1 2

3. Water Resources: Distribution2
Water covers 2/3 of earth
97% of water on Earth is salt water in ocean & seas
2.5% is Frozen freshwater in glaciers
77% of all freshwater is frozen
0.5% is available freshwater
on surface or in ground
Day 1 3

4. Surface Water Surface H2O = lakes, rivers, streams, wetlands3
Surface H2O = lakes, rivers, streams, wetlands
Rivers especially important for human civilizations
River system: flowing network of water that forms from streams
Amazon*, Mississippi, Nile
Watershed: area of land drained by a river
Ex: Amazon River Basin
Day 1 4

6. Water Cycle 4
Water is a Renewable Resource - circulated in the water (hydrologic) cycle:
Evaporation (liquid → vapor in clouds)
Condensation (vapor → liquid; in atmosphere)
Precipitation
(rain, sleet, snow)
Surface Runoff
(back to oceans)
Note: can still deplete
or ruin it
Day 1 6

7. Groundwater Most available freshwater exists underground5
Most available freshwater exists underground
Groundwater: water beneath Earth’s surface in soil & rock
Day 1 7

8. Groundwater 6
Aquifer: underground formation that contains lots of groundwater
H2O is between rock, sand, & gravel
Upper boundary of aquifer = water table
Getting H2O depends on:
Porosity: amount of space b/w rock & soil (H2O is stored in pores)
Permeability: ability of rock or soil to allow H2O to flow
Day 1 8

9. Groundwater How does water get to aquifer?:7
How does water get to aquifer?:
Recharge zone: area where H2O percolates down
H2O must travel through permeable layers of soil
Where aquifers are sensitive to pollution!
Well: hole that is dug or drilled to reach groundwater in aquifer
Must be below water table, or can dry up
Day 1 9

10. Groundwater Groundwater Problems: Overdrawing – wells runs dry7
Groundwater Problems:
Overdrawing – wells runs dry
Pollution: oil, chemicals, salt water
Pavement prevents recharge
Video:
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Day 1 10

11. Different Types of Wells: Unconfined vs
Different Types of Wells: Unconfined vs. Confined (artesian) Assignment: Draw On Paper & Color– Include All Words! 11

12. Water Use & Management Three major uses of H2O:
Agriculture: irrigation
Industries
Residential – drinking & washing
Day 2
Average person in US uses 300 L (80 gallons) / day 12

13. Water Use: Industrial Accounts for 19% of water used in world Used to
manufacture goods
dispose of waste
Generate power
Cool power plants
Use & return water from lake or river → Thermal pollution??
Day 2 13

14. Water Use: Residential Use
Water from toilet, dishwasher, bath, etc. enters sewers & must be treated
Why Treat Water?
Sewage: human wastes, paper, soap, detergent, food, bacteria, etc.
Three-step process 2. 3.
Day 2 5. 14

15. Water Treatment: 2. Secondary Treatment: 3. Tertiary Treatment:
1. Primary Treatment:
Removes large solid objects (trash, diapers) & sand/grit
2. Secondary Treatment:
Removes organic matter & kills microorganisms
Oxygen is added for decomposition
Is disinfected with chlorine to kill bacteria & viruses
3. Tertiary Treatment:
= chemical or physical reactions to remove pollutants (phosphates, nitrates, salts, pesticides)
Fluoride is added to drinking water 2. 3.
Day 2 5. 15

16. Water Management
Dam = structure built to control river flow; creates a reservoir = artificial lake
Provides:
Drinking water
Irrigation water
Recreation
Hydroelectric dam: uses power of flowing water to turn turbine to generate electricity
Problems with dams: flooding; prevents animal migration; pollution
Day 2 16

17. Ways to Conserve Water:
In Agriculture:
Drip irrigation = water crops directly & little at a time
In Industry:
Recycle & reuse wastewater
In Residential:
Shorter & cooler showers
Low-flow toilets
Aerators in faucets
Wash only full loads
Day 2 17

18. Ways to Conserve Water:
Future Solutions to Water
Availability Issues:
Desalination = process of removing salt from ocean water
Expensive b/c of power requirements
Towing Icebergs? - research says too costly
Cloud Seeding - silver iodide crystals makes water droplets form if cloud is present
Used in China
Day 2 18

19. Water Pollution
Water Pollution = when chemical, physical, or biological agents get into water and lowers quality & negatively affects organisms
Two Types:
Point-source Pollution = single source of pollution is known (one factory, one sewage treatment plant)
Nonpoint-source Pollution = many different sources over a wide area
-road chemicals
-agricultural
chemicals
Day 3 19

20. Water Pollution Pollutants Include:
Pathogens (bacteria, viruses, worms)
Organic matter (feces, food waste, bodies)
Chemicals (pesticides, oil, plastics, etc.)
Heavy metals (lead, mercury, arsenic)
Thermal pollution: Lowered water quality due to change in water temperature (influx of hot water)
lowers levels of dissolved oxygen & can cause large fish kills
Occurs next to power plants & factories
Day 3 20

21. Water Pollution cont.
Eutrophication: accumulation of nutrients in a lake or pond – natural process happens over time
Artificial Eutrophication: increased amounts of nitrogen & phosphorus due to fertilizers
speeds up plant growth and eventually choke the water of all of its animal life
Day 3 21

22. Ground Water & Ocean Pollution
Ground Water Pollutants:
Surface water pollution
Leaky storage tanks (gas, septic, chemicals)
Landfills
Difficult/ impossible to clean up
Ocean Pollutants:
Land runoff
Oil spills
Beach trash
Day 3 22

23. Water Pollution & Ecosystems
Biomagnification = build up of pollutants at higher levels of the food chain
Examples: DDT enters body of zooplankton, a hundred of these organisms are eaten by a small fish, a hundred of these fish are eaten by a bigger fish, an eagle eats ten of these big fish, the concentration of DDT is magnified in the eagle
Enters food chain → humans
Day 3 23

24. Water Regulation Clean Water Act (1972) Other laws:
Set goals for clean water; required metals to be removed from wastewater
Other laws:
Marine Protection, Research, & Sanctuaries Act (1972; 1988) – controlled dumping of sewage & toxic waste into water
Safe Drinking Water Act (1975, 1996) – protects groundwater; standards for water quality
Oil Pollution Act (1990) – all oil tankers must be double-hulled by 2015 24