How does water underground reach the surface?

1
How does water underground reach the surface?

• Freshwater flows underground.

2
Water moves underground.

• All groundwater comes from precipitation.
• Water underground trickles down between particles
  of soil and through cracks and spaces in layers
  of rock.

3
Groundwater Formation

• Differences in the materials that form layers
  underground determine where groundwater forms.

4
Different Materials

• The size of the pores determines how easily water
  moves through rock and soil.
• Permeable allow water to pass through. Large
  connected pores Ex) sand, gravel
• Impermeable water cannot pass through easily.
  Few or no pores or cracks. Ex) clay, granite

5
Water Zones

• Saturated Zone area of permeable rock that is
  totally filled with water.
• Water Table top of the saturated zone.
• Unsaturated Zone layer of rocks and soil above
  the water table.

6
Bringing Up Groundwater

• Aquifer underground layer of rock that holds
  water.
• People can obtain groundwater from an aquifer by
  drilling a well below the water table.
• The level of a water table follows the shape of
  underground rock layers.
• Water level can rise during heavy rains and then
  fall in times of drought.

7
Drilling for Water
8
Drilling For Water

• Pumping water out of an aquifer lowers the water
  table near the well. If too much water is pumped
  out too fast, the well could run dry.
• New water that enters an aquifer from the surface
  is called recharge.
• Artesian Well water rises to the surface b/c of
  the pressure w/in the aquifer. Occurs when water
  is trapped between layers of impermeable rock.
  Released when the top layer is punctured and
  natural pressure sends the water spurting upward.