AIM: What is the Water Table?

Do Now:

Looking at the 3 jars below, describe the Permeability, Porosity and Capillarity of each.

I. What is the Water Table?

- Zone of Aeration

pore space contains mostly air.

- Zone of Saturation

pore space contains mostly water.

A. Water TableThe top of the zone of saturation. This

boundary moves as evaporation and precipitation occurs

B. Groundwater is the water within the zone of saturation.

- Movement depends on porosity and permeability of the rock

C. Aquifer – permeable rock layers or sediments that transmit groundwater freely. This supplies a town or city with water.

1. Springs - form when the water table intersects the ground surface.

- Hot SpringsWater is heated by cooling of igneous rock or magma near the surface.

II. Important water Features

2. Geysers – heated pressurized water that is forced out of the ground.

Old Faithful, Yellowstone National Park, Wyoming

- Heat comes from magma

3. A well is a hole into the zone of saturation.

1) An artesian well occurs when groundwater rises on its own under pressure.

2) Pumping can cause a drawdown (lowering) of the water table.

3) Pumping can form a cone of depression in the water table.

III. Groundwater Contamination

- Overuse and contamination threatens groundwater supplies in some areas.

- Treating it as a nonrenewable resource.

- Land subsidence caused by its withdrawal.

IV. Karst Topography

- Formed by dissolving rock at, or near, Earth's surface.

- Area lacks good surface drainage.

- A cavern is a naturally formed underground chamber.

- Formed in the zone of aeration.

- Stalactites – hanging from ceiling.

- Stalagmites – growing upward from the floor.

Formed from calcite deposited as dripping water evaporates.

V. Common Features

1) Sinkholes - surface depressions.- form when bedrock dissolves and

caverns collapse.

2) Caves

Sinkholes

Sinkholes Truck in Sinkhole Car Sinkhole