1. Water Underground

2. How does water move underground?
Water trickles down between particles of soil and through cracks and spaces in layers of rock
Different types of rock and soil have different sized spaces
The size of the pores and the connections between them, determines how easily water moves

3. Permeable?
Soil and rock that allows water to pass through is called permeable
Other materials like clay have very small pores, so water cannot pass through
Materials that water cannot pass through are called impermeable

4. Water Zones
When water from precipitation, passes down through permeable rock, the ground begins to saturate
When the water gets deep enough it reaches the saturated zone, where the pores are full
The top of the saturated zone is called the water table

5. How do people use groundwater?
An underground layer of permeable rock that holds water and allows it to flow is an aquifer
The huge Ogallala aquifer reaches from South Dakota all the way into Texas
People can get water from an aquifer by drilling a well below the water table

6. Pumps and Pressure
An artesian well is where water rises on its own because of pressure within an aquifer
Water becomes trapped between two layers of impermeable rock and the pressure builds until that rock is punctured