Ground Water

Beth Roland

Eighth Grade Science

Team 5- Mountaineers

Ground Water...An underground lake

• Zone of Aeration– Water easily passes

through the uppermost zone

– As water percolates, contaminants and particles are filtered out of the water

• Zone of Saturation– Water collects

between the spaces of rock particles and creates an underground “lake”

Ground Water is water that is located within the rocks below the Earth’s surface.

What lies between

• The water table is the boundary between the zone of aeration and saturation

• The water table varies in depth from a few centimeters below the soil surface to hundreds of meters below the Earth’s surface– Water table rises during wet seasons – Water table falls during dry seasons

The water cycle revisited

Exactly what is an Aquifer?

• An Aquifer is a rock layer in which ground water can freely flow– Characteristics of an Aquifer

• Porosity (pores or spaces)- the more space between particles of an aquifer the more water it can hold

• Larger particles= more porous smaller particles= less

porous

Additional Characteristics

• Permeability (permeate)- the ability of a rock layer to let water pass through– Larger particles = less surface area and less

friction therefore more permeable– Smaller particles = more surface area and

more friction therefore less permeable

Best of the Best Sir~!

• The best aquifers form in permeable materials such as sandstone, limestone, or layers of sand and gravel.

• An aquifer depends on the water cycle to continuously recharge itself.

• Water enters an aquifer through a surface recharge zone the is permeable for water to percolate through easily.

Springs and Wells Oh my!

• Springs– When the water table

reaches the Earth’s surface, a spring forms

– If the table is higher than the Earth’s surface, a lake is created

– Springs are important sources of drinking water

• Artesian Springs– Unlike a regular

spring, an artesian formation occurs when an aquifer is sandwiched between 2 layers of impenetrable rock.

– An artesian spring occurs in a crack of the cap rock

Wells

• A human made hole that is deeper than the level of the water table is called a well. – Can dry up if the water table drops below the

well– Additionally, can be depleted if too many wells

access the aquifer and water is removed too quickly