AQUIFER

Figure 1 : Aquifer

What is it basically?

1. A formation, group of formations, or part of a formation that contains sufficient saturated, permeable material to yield significant quantities of water to wells and springs.
2. An underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, silt, or clay) from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology.
   
3. Related terms include: an aquitard, which is an impermeable layer along an aquifer, and an aquiclude (or aquifuge), which is a solid, impermeable area underlying or overlying an aquifer.
   
4. The surface of saturated material in an aquifer is known as the water table.

Figure 2 : Aquifer (natural sources of clean water)

Where we can visualize it?

• Aquifers can occur at various depths.
  
• The beach provides a model to help visualize an aquifer.
  
• If a hole is dug into the sand, very wet or saturated sand will be located at a shallow depth.
• This hole is a crude well, the wet sand represents an aquifer, and the level to which the water rises in this hole represents the water table.

Why aquifers (natural sources of clean water) are so important?

• About seventy percent of the earth's surface is covered with water.
  
• Only one percent is fresh water, flowing through rivers, lakes, and underground streams.
• Much of that has already been polluted by humans. Not many animals live in its water because it doesn't yet contain enough oxygen to support much life.
  
• Water mites, scuds or "sideswimmers," black fly or caddis fly larve, and occasionally beetles, snails, and salamanders may live in the cold water.

Figure 3 : Aquifer recharge