1.3: Fresh Water Flows Underground

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1.3 Fresh Water Flows Underground

• Groundwater Water held underground
• Permeable A substance that liquids can flow
  through. Ex coffee filter, soil, sand and
  gravel.
• Impermeable A substance that liquids cannot flow
  through.

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• Ex A drinking glass holds liquids because it is
  impermeable.
• Clay is soft, but it is nearly impermeable.
• Groundwater collects because gravity causes
  rainwater to sink into the soil. Water sinks
  though permeable ground until it reaches an
  impermeable layer.

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• Water table The top of the area of groundwater
  that is saturated or completely filled with
  water. This is called the saturation zone.
• Groundwater may collect in the spaces within
  soil, gravel and some kinds of rock.

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Aquifers

• An aquifer is an underground layer of permeable
  rock that contains water. Some lie deep under
  impermeable rock, and others lie just beneath the
  topsoil.

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3 Things Must Occur for an Aquifer to Form (pg.
26)

• 1. Groundwater is stored in the pore spaces of
  gravel and rock in a layer of permeable material.
• 2. A neighboring area of impermeable rock keeps
  the water from draining away.
• 3. A source of water refills the aquifer.

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Importance of Aquifers

• The ground acts like a giant filter. Stones and
  sand in the ground can filter out bacteria. It
  removes harmful chemicals and minerals. It keeps
  water cleaner and more ready to drink.

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Springs and Wells

• A spring is a flow of water from the ground at a
  place where the surface of the land dips below
  the water table.
• A well is a hole in the ground that reaches down
  to the saturation zone- the wet region below the
  water table.

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• Most wells need a pump to draw up the water and
  are dug with motorized drills.
• An artesian well does not need a pump. The water
  flows to the surface naturally because it is
  under pressure.

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• The depth of the water table can vary from season
  to season, depending on the amount of rainfall.
• If water is used faster than it is replaced,
  wells may run dry causing the ground to settle
  and damage the environment.

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Hot Springs

• Hot Springs- Hot water deep underground that is
  like an enormous boiling pot. Water heats to the
  boiling point and then becomes hotter because the
  liquid is under great pressure from the
  surrounding rocks.
• A geyser is a kind of hot spring.