1. Humans and Water

2. Humans and Water Objectives:
Explain why fresh water in one of Earth’s limited resources.
Describe the relationship between groundwater and surface water in a watershed.
Identify how water is used in homes, industry, and agriculture.
Describe water management practices.
Identify ways that water can be conserved.
Compare point source pollution and non-point source pollution.
Explain groundwater pollution.
Explain eutrophication

3. Humans and Water Important Vocabulary: Surface water Desalination
Watershed
Groundwater
Aquifer
Recharge zone
Irrigation
Canals
Dams
Desalination
Point Source Pollution
Non-point Source Pollution
Runoff
Eutrophication
Thermal Pollution
Wastewater

4. Global Water Distribution
71% of the Earth’s surface is covered with water
97% of Earth’s water is salt water
77% of fresh water is frozen in glaciers and polar ice caps

5. Surface Water
Freshwater is found in lakes, rivers, streams, and wetlands
Watershed – the area of land that is drained into a body of water

6. Groundwater
Most freshwater available for human use comes from groundwater
Groundwater is stored beneath the Earth’s surface in rock formations
Rain percolates through the soil and into the rock beneath it to recharge the groundwater supply

7. Aquifers Aquifers are underground formations that contain groundwater
The water table is the upper boundary
Aquifers consist of rock, sand, and gravel that have spaces where water accumulates

8. Aquifers, cont.
Recharge zone – the area of the Earth’s surface where water percolates down into the aquifer
Well – a hole that is dug or drilled to reach groundwater

9. Example - Ogallala Aquifer
One of the largest known aquifers in the world – holds about 4 quadrillion liters of water
Supplies about 1/3 of all groundwater used in the U.S.
Water is used for irrigation in the Midwest
Water is being withdrawn 10 – 40 times faster than it is replaced
Conservation methods are being promoted to protect the Ogallala Aquifer

10. REMEMBER THIS!!! Only 3% of the world’s water is freshwater!
Most freshwater for human use comes from groundwater!
In some areas, water from aquifers is being withdrawn faster than it is being replaced!

11. Questions???
Question 1: What is the main source of water for human use?
Question 2: The area of land drained by a river is known as a _______________.
Question 3: What is the largest known aquifer in the U.S.?

12. Water Use and Management
Industrial 19%
Agricultural 67%
Residential 8%
Differs from one country to the next
U.S. uses more than other countries
Example: U.S. uses about 300 liters of water a day; India uses about 41 liters

13. Industrial Use Used to: Manufacture goods Dispose of waste
Generate power/cool power plants
Example: Calvert Cliffs Nuclear Power Plant pumps water from the Bay, carries the water through pipes to use during energy production before it is sent to a cooling tower, and then pumps it back into the Bay

14. Agricultural Use
Irrigation – method of providing plants with water from sources other than precipitation
Example: overhead sprinklers, water filled ditches
It can take nearly 300 L of water to produce one ear of corn
As much as 80% of the water used evaporates and never reaches the roots

15. REMEMBER THIS!!!
The U.S. uses much more water than many other countries!
Agriculture uses the most water!
It takes hundreds of gallons to produce food because crops must be irrigated!

16. Water Management Projects
Canals, man-made rivers, supply water to dry areas
Dams
Positive Aspects include:
Creates Reservoirs; lake that forms behind the dam
can be used for recreational purposes
Controls flooding
Supplies potable (safe to drink) water
Generation of electricity
Drawbacks: impedes fish migration for spawning; fewer nutrients downstream;expensive to build

17. Water Conservation Drip irrigation system – reduces evaporation
Recycling cooling water in power plants
Things you can do to conserve water:
Take shorter showers
Low-flow shower heads and toilets
Turn off water while brushing teeth
Wash only full loads of laundry
Water lawns late in the day to reduce evaporation

18. Solutions for the Future
Transporting water – ships tow enormous plastic bags full of fresh water to areas that don’t have a lot of fresh water
Desalination – process of removing salt from salt water
Both are expensive solutions
CONSERVATION

19. REMEMBER THIS!!!
Dams can be used to create electricity, provide recreation, potable water, and control flooding!
There are many simple things you can do to conserve water!
Water conservation is the best way to ensure that people have enough water in the future!

20. Questions???
Question 4: What are the three major uses of water? Which uses the most water?
Question 5: List three benefits of a dam.
Question 6: List three ways you can conserve water.

21. Water Pollution .
The introduction of a chemical, physical, or biological agents that enter into water and degrades the water quality as well as adversely affects the organisms that depend on the water.

22. Point-Source Pollution
pollution discharged from a single source - you can POINT at the source
Example: From a pipe
Example: Smokestack
Example: Tailpipe

23. Non-point Source Pollution
- comes from many sources - often in the form of runoff

24. Groundwater Pollution
Pollutants enter groundwater when polluted water percolates down from the Earth’s surface
Saltwater can enter groundwater when water is removed from an aquifer

25. Eutrophication
Overabundance of nutrients builds up in the water causing algal blooms
SAV below dies due to lack of sunlight
Decomposers use up the oxygen in the water as they eat the SAV causing other aquatic organisms to suffocate and die
Process is accelerated with the addition of detergents (phosphorus) and fertilizers (phosphorus and nitrogen) – called “artificial eutrophication”

27. Other Water Pollutants
Thermal pollution – temperature of the water increases due to human activities
can change the ecosystem and kill aquatic organisms
Oil spills – responsible for only 5% of oil pollution in the oceans; most other oil pollution comes from non-point sources on land
Wastewater – water that contains waste from homes or industries

29. REMEMBER THIS!!! Point Source pollution comes from a single source!
Non-point Source pollution comes from many sources in the form of runoff.
Saltwater can enter an aquifer from excessive pumping of groundwater!
Eutrophication may cause dead zones that are initiated by excessive nutrients being added to an aquatic ecosystem!

30. Questions??? Question 7: Describe point source pollution.
Question 8: Provide an example of non-point source pollution.
Question 9: Artificial eutrophication is caused by excess ___________________ and ________________.
Question 10: Where does most oil pollution come from?

31. THE END!!!