1. Ground Water Systems

2. VA SOL
SOL 9 The student will investigate and understand how freshwater resources are influenced by geological processes and the activities of humans. Key concepts include
b. development of karst topography
c. identification of groundwater zones including the water table, zone of saturation, and zone of aeration;
e. dependence on freshwater resources and the effects of human usage on water quality;

3. Objective
1. Describe underground water sources (such as aquifers and springs).
2. Explain how geologic processes such as erosion and human activities such as waste disposal can pollute water supplies.
3. Describe point source (e.g. sewers, waste pipes) and non-point source (e.g. sanitary landfills, runoff of pesticides) water pollution.

4. Enduring Understanding
Weathering, erosion, and deposition are interrelated processes that form a cycle of forces that wear down and build up the Earth’s surface.
Water is continuously passed through the hydrologic cycle.
Fresh water is necessary for survival and most human activities.

5. Ground Water Systems
Groundwater moves slowly but continuously through aquifers on its journey back to the oceans.

6. Ground Water Systems
The average length of time that groundwater remains underground is several hundred years.

7. Ground Water Systems
Groundwater can return to the surface at places where the water table intersects Earth’s surface

8. Ground Water Systems
Springs emerge where an aquifer and aquiclude come in contact at the surface

9. Ground Water Systems
Limestone and sandstone formations, sand and gravel are common aquifers

10. Ground Water Systems
Clay and shale layers are aquicludes

11. Ground Water Systems
Many of the lakes in Karst regions such as Florida are flooded sinkholes that are fed by springs

12. Ground Water Systems
Hot springs have water temperatures higher than the human body and are common in the western United States where the subsurface is still hot from recent igneous activity

13. Ground Water Systems
Geysers are explosive hot springs that erupt at regular intervals

14. Ground Water Systems
Old Faithful, located in Yellowstone National Park in Wyoming is a famous geyser

15. Wells
Many homes in Norfolk use well water for lawns, utility, and even drinking water

16. Wells
Well is a hole dug or drilled into the ground to reach a reservoir of groundwater

17. Wells
Simple wells are dug below the water table into the zone of saturation

18. Wells
Cone of depression is a lowering of the water table around the head of a well

19. Wells
Drawdown is the difference between the original water table level and the level in the pumped well

20. Wells
Recharge is when precipitation and runoff is added back to the zone of saturation

21. Wells
If recharge does not keep pace with drawdown the wells in an area will go dry

22. Confined Aquifers
Water table aquifers are unprotected and exposed to pollutants. Confined aquifers are sandwiched between aquicludes that form barriers that prevent pollutants from reaching the ground water

23. Confined Aquifers
Artesian wells contain water under pressure between two aquicludes

24. Confined Aquifers
The pressure is caused by the recharge areas being at a higher elevation

25. Water Quality
Freshwater is Earth’s most precious natural resource. Because of its natural filtering and availability groundwater is the main source of this vital need.

26. Water Quality
Many geologic processes such as erosion can have harmful effects on our freshwater supplies

27. Water Quality
Subsidence is the sinking of land elevation when too much groundwater is removed

28. Water Quality
In coastal areas such as Norfolk salt water contaminates the freshwater supplies and makes well water undrinkable

29. Water Quality
It is also believed that a meteor strike near the mouth of the Chesapeake Bay 35 million years ago contaminated the aquifer by crystallizing the salts in the seawater into the parent bedrock

30. Water Quality
Industrial and harmful chemical wastes from improperly constructed or maintained dumpsites (or illegal dumping) can contaminate groundwater for many miles around the source

31. Water Quality
Chemicals in solution cannot be filtered by the fine-grained sediments

32. Water Quality
It is important to realize that protecting our water supply is of vital importance.

33. Water Quality
It is our responsibility to be aware of how human activities affect our resources and act (and vote) accordingly!