Water Underground

groundwater permeable impermeable saturated zone unsaturated zone aquifer water table

How Water Moves Underground Water underground trickles down between particles of soil and through cracks and spaces in layers of rock

Effects of Different Materials Permeable materials have large and connected pores; materials such as sand and gravel allow water to pass through or permeate. Impermeable materials have few or no pores or cracks; therefore the water cannot pass through easily Examples: clay and granite

Water Zones **The area of permeable rock or soil that is totally filled or saturated, with water is called the saturated zone** **The top of the saturated zone is called the water table** The area above the water table is called the unsaturated zone

Bringing up Groundwater In some areas, the water table meets the surface Aquifers: Any underground layer of rock or sediment that holds water is known as an aquifer** Size: small underground patch to the size of several states

Aquifers continued Functions: drinking water, water for crops, and water for livestock Rate of Movement: depends on the slope of the aquifer and permeability of rocks

Wells **People can obtain groundwater from an aquifer by drilling a well below the water table** If the level of the aquifer drops, a well can run dry The water table can rise after heavy rain or snow melts

Using Pumps Mechanical pumps bring up groundwater If water is pumped out too fast, a well will run dry New water that enters the aquifer from the surface is called recharge

Relying on Pressure **In an artesian well, water rises because of pressure in an aquifer** If groundwater becomes trapped between two layers of impermeable rock or sediment, the pressure sends water spurting up through the punctured hole No pump is necessary

Springs and Geysers Sometimes, groundwater comes to the surface through natural processes When groundwater bubbles or flows out of cracks in the rock it is called a spring A fountain of boiling water is known as a geyser

Springs and Geysers The word geyser means gusher A geyser forms when very hot water that has been circulating deep underground begins to rise through narrow passages in the rock Provide one example of a geyser: Old Faithful

Which wells end in a saturated zone? Which well(s) will not provide water? How does water enter Aquifer A?

Interesting Sites http://unmuseum.mus.pa.us/flash/geyflash.htm http://www.nps.gov/archive/yell/oldfaithfulcam.htm http://www.floridasprings.org www.unitedstreaming.com (Gushing Geysers; Natural Phenomena)