Groundwater

1
Groundwater

• Water that moves downward into Earths surface
  due to gravity.
• Water stored underground in pore spaces of rock
  layers.
• Water in soil or rock that supplyies springs and
  wells.

2
Aquifers

• a geologic formation that stores and/or
  transports water
• Unconfined aquifer has permeable layer above
• Confined aquifer has impermeable layers both
  above and below it may also be under pressure

3
Permeable and Impermeable Layers

• permeable material allows water to pass through
  (sponge, bread, sandstone)
• impermeable materials do not allow water to pass
  through also called aquitards or aquicludes
• Examples of this type of material include
• clay shale
• bedrock granite

4
The water table is the top of the water surface
in the aquifer. Wells are used to get the water.
5
The saturated zone is the area beneath the water
table where ALL pore spaces are filled with
water.There is NO air in this zone.
6
Both air and water exist in the pore spaces of
the unsaturated zone above the water table.
7
Sometimes a well has to go through an impermeable
layer to reach an aquifer.
8
In an artesian well, the pressure in the confined
aquifer forces water up the well without a pump.
9
The cone of depression is created when the well
is pumped. The water in the aquifer dips toward
the well.
10
The drawdown is the difference between where the
water table was before and after the pump for the
well is turned on to create the cone of
depression.
11
Recharge areas are surface areas where water
seeps in and flows down to refill the aquifer. An
aquifers recharge area may be far away.
12
Contamination of aquifers occurs from the
surface. Since groundwater moves slowly,
contamination continues for many, many years.