1. Groundwater Systems
Chapter 10
Section 3

2. Springs Natural discharges of groundwater Occur in various places
- sides of valleys
- edge of perched water table
- along faults
- sometimes feed lakes/fill sink holes
Volume of water varies
From a small spring to a large river

4. Virginia

5. Temp. of Springs Depends on where they are located
Usually colder in the summer & warmer in the winter (compared to air temp)
Hot Springs – have temps higher than that of the human body
Thousands in the US
Mostly in the western US

8. Geysers Explosive hot springs that erupt @ regular intervals
Most Famous –Old Faithful (Yellowstone Nat’l Park – Wyoming)
Erupts every hour with 40 m (131 feet) high column of boiling water & steam

11. Wells
Holes dug or drilled deep into the ground to reach a reservoir of groundwater
MUST tap into aquifers (ZOS)
Drawdown – the difference between the original water-table & the water level in the pumped well (too many wells tapped into same aquifer may cause their “cone of depressions” to overlap causing the well to run dry!
Recharge – Water that helps re-fill the zone of saturation/water table “recharges” it. (Ogallala)
Recharge < drawdown = dry well!
*Artesian well – Super high recharge=great pressure and when a well taps into a confined aquifer with high pressure, it may spurt up like a fountain

15. Aquifer – Underground material that allows water to flow
Aquiclude – underground material that does NOT allow water to flow
Unconfined Aquifer – completely open to surface on one side
Confined Aquifer – trapped between two aquicludes

17. Threats to Our Water Supply
Overuse, Sewage, Industrial waste, Landfills, Agricultural chemicals
Subsidence – ( Sinking) from over-pumping
Pollution in Groundwater (main 4 on next slide)
(*if recharge area of a confined aquifer
becomes polluted, the aquifer will too)
Chemicals – form “plumes”
that USUALLY spread slowly
Salt – from over-pumping in coastal areas.
Radon – from radioactive
decomposing uranium. (Colorless, odorless gas; naturally occurring)

18. Greatest Sources of Pollution:
Sewage
Industrial waste
Landfills
Agricultural chemicals