1. Gaining vs. losing streams
Source: U.S.G.S.

2. Effects of pumping on GW - surface water interaction
Source: U.S.G.S.

3. Schematic showing basic elements of an unconfined aquifer system
Source: U.S.G.S.

4. Example of a perched water table and its relationship to the regional unconfined aquifer system

5. Layered aquifer system(s), showing confined aquifer beneath an unconfined aquifer. Note the artesian conditions in the valley.

6. Aquifer in fractured volcanic rocks (Kona, HI)
Source: U.S.G.S. National Groundwater Atlas

7. Regional aquifers in the Mid-Atlantic U.S.
Fractured limestone and metamorphic rock
Unconsolidated sediments & sedimentary rock
Source: U.S.G.S. National Groundwater Atlas

8. Locations of major sandstone aquifers in the U.S.
Source: U.S.G.S.

9. Example showing porosity (note that for illustration purposes, the sand grains are shown to be unrealistically far apart)
Types of porosity

10. Example showing porosity in a thin section of sandstone

11. Hydrostatic Head: An Example...
Which way does the groundwater flow?
10 m
3 m
0 m

12. What is the head at each point?
10 m B
Pressure head = 7 m
Elevation Head = 3 m
Total Head = 10 m
3 m A C
0 m

13. What is the head at each point?
10 m B
Pressure head = ?? m
Elevation Head = ?? m
Total Head = ?? m
3 m A C
0 m

14. What is the head at each point?
10 m B
Pressure head = 0 m
Elevation Head = 10 m
Total Head = 10 m
3 m A C
0 m